Hello Everyone!

Let's tackle this question, one problem at a time, and narrow it down to the correct choice! Before we get started, here is the original question with any major differences between the options highlighted in orange:

Researchers studying the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is emotion, not logic or analytical reasoning.

(A) the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is
(B) the brain scans of volunteers who pondered ethical dilemmas and found the basis to make tough moral decisions to be
(C) the brain scans of volunteers pondering ethical dilemmas and found that the basis for making tough moral decisions is
(D) volunteers’ brain scans while pondering ethical dilemmas have found the basis to make tough moral judgments to be
(E) volunteers’ brain scans while they pondered ethical dilemmas have found that the basis for making tough moral judgments is

After a quick scan over the options, there are a few things we can focus on to narrow down our choices:
1. the brain scans of volunteers / volunteers' brain scans
2. have found / and found
3. for making / to make
4. is / to be

Let's start with #1 on our list: the brain scans of volunteers vs. volunteers' brain scans. While it seems like these two phrases could be interchangeable, they are not! Let's take a look at each option with the beginning of the sentence plugged in to see the difference:

(A) Researchers studying the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is --> OKAY
(It's clear that the researchers are studying brain scans from volunteers who were pondering ethical dilemmas.)

(B) Researchers studying the brain scans of volunteers who pondered ethical dilemmas and found the basis to make tough moral decisions to be --> OKAY
(It's clear that the researchers are studying brain scans from volunteers who were pondering ethical dilemmas.)

(C) Researchers studying the brain scans of volunteers pondering ethical dilemmas and found that the basis for making tough moral decisions is --> OKAY
(It's clear that the researchers are studying brain scans from volunteers who were pondering ethical dilemmas.)

(D) Researchers studying volunteers’ brain scans while pondering ethical dilemmas have found the basis to make tough moral judgments to be --> INCORRECT
(The meaning of this sentence is unclear! Who was pondering ethical dilemmas? You could make a case that the researchers are pondering ethical dilemmas, or maybe the volunteers are? If it's not 100% clear, let's eliminate it due to vagueness!)

(E) Researchers studying volunteers’ brain scans while they pondered ethical dilemmas have found that the basis for making tough moral judgments is --> INCORRECT
(This is also unclear, thanks to the vague pronoun "they." WHO pondered ethical dilemmas? It's not clear at all if the pronoun "they" is referring to researchers or volunteers, so let's rule this one out too!)

We can eliminate options D & E because they include vague phrases or pronouns, which is a big no-no on the GMAT!

Now that we're left with 3 options, let's move on to #2 on the list: and found vs. have found. This is a verb issue, so let's take a look at each option with the rest of the sentence plugged in to spot the problem. To make it easier, I've also highlighted the subject of the sentence. It should be clear to you what the subject and verb are, and they should agree:

(A) Researchers studying the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is emotion, not logic or analytical reasoning.

This is CORRECT! It's clear that the researchers were the ones who found that the basis for making judgements is emotion, not the volunteers!

(B) Researchers studying the brain scans of volunteers who pondered ethical dilemmas and found the basis to make tough moral decisions to be emotion, not logic or analytical reasoning.

This is INCORRECT because it changes the intended meaning. This sentence states that the volunteers pondered ethical dilemmas AND found the basis of making tough decision to be emotions. This isn't true - the researchers are the ones who found it!

(C) Researchers studying the brain scans of volunteers pondering ethical dilemmas and found that the basis for making tough moral decisions is emotion, not logic or analytical reasoning.

This is also INCORRECT because it changes meaning. It also gives the volunteers credit for finding the basis of making tough decisions, not the researchers!

There you have it - option A was correct all along! If we focus on one problem at a time, we can narrow down the options quickly and arrive at the right answer!


Don't study for the GMAT. Train for it.
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Meaning:
1. Researchers studied Brain scans of volunteers
2. Volunteers – pondered ethical dlemmas
3. Researchers found that Basis is emotion not logic or analytical reasoning.


Error Analysis
Researchers
<Ving modifier modifies researchers > studying the brain scans of volunteers (Relative pronoun referring to Volunteer) who pondered ethical dilemmas

Have found
That “basis for making tough moral judgments” (subject – singular) is emotion not logic or analytical

No subject verb error,
No modifier error.

Option A is correct as Is.

Lets do POE to make it sure.

(B) the brain scans of volunteers who pondered ethical dilemmas and found the basis to make tough moral decisions to be
No verb for subject Researchers
Illogical meaning “Volunteers pondered and found”

(C) the brain scans of volunteers pondering ethical dilemmas and found that the basis for making tough moral decisions is
Subject without verb “Researchers Blah blah and Found” part before and does not have any verb

(D) volunteers’ brain scans while pondering ethical dilemmas have found the basis to make tough moral judgments to be
Highly illogical meaning
Researchers while pondering, have found

(E) volunteers’ brain scans while they pondered ethical dilemmas have foundthat the basis for making tough moral judgments is
Incorrect same as option D

One more solution:

Sentence Meaning -
Researchers have found the basis for making tough decisions. How? Studying the brain scans of volunteers (certain kind of vounteers - who pondered ethical dilemmas).

Elimination Strategy:

- Splits 2/3 - the brain scans or volunteers' brain scans

- D & E - wrong - Volunteers' brain scans - ambigous and avoidable in GMAT (mostly)

- B & C - wrong - No verb before "And". (Not following parallelism) X and Y. Y has verb (found) and X contains NO verb.

Correct Answer : A

Note: "There are other errors too (logical as well as grammatical). The idea is to perform "IN" & "OUT" of the question quickly.

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Researchers studying the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is emotion, not logic or analytical reasoning.

A) the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is

From my point of view, the meaning of the correct answer (option A) is not totally precise and, hence, the sentence could be improved.

It says "the brain scans of volunteers who pondered ethical dilemmas". Well, everyone (or almost everyone) pondered ethical dilemmas in the past. Hence, this is somehow vague or inconcrete.

The idea would be better expressed if it said something like "the brain scans of volunteers while they pondered ethical dilemmas".

Your thoughts on this idea will be greatly appreciated.

Researchers studying the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is emotion, not logic or analytical reasoning.

Correct Grammatical Usages -

Researchers ===> have
Correct Idiomatic usage ===> Basis for
Basis for something is is X not Y

Completely agree with the OA (A)
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Thank you for your response Abhishek009, but you did not answer to my question.

Bro , I am sorry for that -

Lets analyze your choice.

Researchers studying the brain scans of volunteers while they pondered ethical dilemmas have found that the basis for making tough moral judgments is emotion, not logic or analytical reasoning.

Here pronoun they has ambiguous antecedent , They can refer to either the Researchers or the volunteers

Further among the given options only (A) seems the best, so correct answer must be (A)


Hope this helps...
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Abhishek009,

I probably did not put the best example as an alternative to the correct answer, but my intention was to cast some doubt on the logicality of that aspect of the correct answer.

Nonetheless, I agree with you. Among all the options, A is the best.

Thank you so much for your responses.

Thanks for bringing this up

What I have learnt from seniors and experts here is that -

1. Never doubt the OA for Official question
2. Do not look for the best possible answer , look for the option which is best among the options given...


Now using strategy (2) I am pretty sure that given the question during actual CAT , we must select the best answer among the options..


Hope that helps..
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Brain Scans
 


First glance

Nearly the entire sentence is underlined, so keep an eye out for the Big Four: Structure, Meaning, Modifiers, and Parallelism.

Issues

(1) Structure: studying…and found

Answers (B) and (C) both insert the word and before found, changing the sentence structure. (A), (D), and (E) use the helper verb have before found instead. Which sentence structure is correct?

Researchers studying…

(A) ...the brain scans...have found that the basis...is emotion
(B) …the brain scans…and found the basis…to be emotion
(C) …the brain scans…and found that the basis…is emotion
(D) ...the brain scans...have found the basis...to be emotion
(E) ...the brain scans...have found that the basis...is emotion

Studying the brain scans modifies researchers. In one interpretation of (B) and (C), the core subject and verb are researchers and found. In this case, there should not be an and between the subject and verb (researchers found). Alternatively, the word found could be seen as parallel to pondered: volunteers who pondered…and found. In this case, there is no main verb connected with the subject researchers at all, since all of the verbs are contained within modifiers. Under either interpretation, neither (B) nor (C) is a complete sentence; eliminate both. In (A), (D), and (E), the core subject and verb are researchers have found; this is correct.

(2) Idiom: the basis to make

The answer choices flip back and forth between the basis for making and the basis to make.

The correct idiom is the basis for: the basis for doing X is Y. Eliminate answers (B) and (D).

(3) Topic: Modifier / Meaning: while pondering

Pronoun: while they pondered

The opening structure of each choice changes.

(A) & (B) the brain scans of volunteers who pondered
(C) the brain scans of volunteers pondering
(D) volunteers’ brain scans while pondering
(E) volunteers’ brain scans while they pondered

While it is possible to construct a correct option starting with volunteers’ brain scans, in this case choices (D) and (E) are faulty. In (D), the sentence reads: Researchers studying X while pondering Y. This parallel structure indicates that the researchers were pondering ethical dilemmas, not the volunteers. While it is possible in general for researchers to ponder ethical dilemmas, that isn't what this sentence describes.

Answer (E) reads: Researchers studying volunteers’ brain scans while they pondered ethical dilemmas. In this case, the pronoun is ambiguous. Logically, the volunteers should be the ones pondering. Since both the main subject researchers and the pronoun they are in subject positions, parallelism suggests that they points to the subject researchers.* Between this choice and answer (A), answer (A) is better because the meaning is unambiguous.

The Correct Answer

Correct answer (A) is a complete sentence and unambiguously indicates that the volunteers, not the researchers, are the ones who pondered ethical dilemmas. It also uses the correct idiom the basis for X is Y.
 
*NOTE: the official explanation says that the pronoun they in answer (E) “must” point to researchers. However other official questions have used a subject pronoun to refer to a possessive noun, including the correct answer for #138 in the 2016 Official Guide for GMAT Review / #805 in the 2017 Official Guide. In the case of #138 / #805, no ambiguity exists because only one noun could possibly function as the antecedent. In the case of the Brain Scans problem, the two potential antecedents create the ambiguity.
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The basic tenet of modification is that if a modifier is not separated from its modified word by a comma, then it modifies only the word before. Therefore, A clearly makes out that it is the volunteers who pondered.
Where is the while mentioned in A? I don't think we need to worry about something that is not mentioned in the text. Can't they study the scans, after the volunteers have completed the pondering? The purpose of a scan I feel is just that
It must be appreciated that D is a blatant modification error. As per D, it means that the volunteers’ brain scans were pondering ethical dilemmas or the researchers were pondering dilemmas and not the volunteers. It is not acceptable. as I see it.
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Researchers studying the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is emotion, not logic or analytical reasoning.

(A) the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is - Correct

(B) the brain scans of volunteers who pondered ethical dilemmas and found the basis to make tough moral decisions to be - no main verb in sentence ;“basis to make” is unidiomatic

(C) the brain scans of volunteers pondering ethical dilemmas and found that the basis for making tough moral decisions is - There is no verb for the subject “Researchers” before “and”

(D) volunteers’ brain scans while pondering ethical dilemmas have found the basis to make tough moral judgments to be - With “while pondering ethical dilemmas”, this option means that researchers studied the brain scans while the researchers pondered ethical dilemmas

(E) volunteers’ brain scans while they pondered ethical dilemmas have found that the basis for making tough moral judgments is - same as D

Answer A
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Researchers studying the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is emotion, not logic or analytical reasoning.

(A) the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is
(B) the brain scans of volunteers who pondered ethical dilemmas and found the basis to make tough moral decisions to be
(C) the brain scans of volunteers pondering ethical dilemmas and found that the basis for making tough moral decisions is
(D) volunteers’ brain scans while pondering ethical dilemmas have found the basis to make tough moral judgments to be
(E) volunteers’ brain scans while they pondered ethical dilemmas have found that the basis for making tough moral judgments is

Please help correct me if my train of thought is incorrect GMATNinja

It seems like (C) and (D) are saying: Researchers are also pondering, whereas original sentence intend to have the volunteers do the pondering.

In (B), Researchers studying ... and found ... to be. and indicates some sort of parallelism and there is nothing.

In (E), while they pondered ... they referring to Researchers? wrong, researchers are not doing the pondering. they referring to brain scans? wrong; brain scans cannot do the pondering.

lary301254M7 I'd say it's D and E that have the researchers doing the pondering. Typically an -ing modifier without a comma modifies the preceding noun, so "pondering" in C still correctly modifies "volunteers." However, C has the same problem with "and found" that appears in B, so that takes care of all but A.
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So to paraphrase

(C) the brain scans of volunteers pondering ethical dilemmas and found that the basis for making tough moral decisions is Brain Scans of volunteers pondering

what is pondering modifying? - volunteers or Scans
Answer - volunteers

Takeaway :-
so a -ing modifier can infact modify a noun in a preposition phrase [u][/u]

Please keep me honest ...... thanks
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Ok guys, look... this is a really tricky question if you get stuck between A and E
VERY SMALL THOUGHT PROCESS
"who" refers to person right before it, so I guess, A is fine in that
now you'll not eliminate E saying that may be researchers could ponder ethical dilemmas. TRUTH BE TOLD, its possible. But since we have a "they" in option E, that could refer to both researchers and brain scans, you can eliminate E based on the ambiguity
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Hi Experts,

Can you explain which is the correct interpretation for the OA?

Researchers studying the brain scans of volunteers who pondered ethical dilemmas have found that the basis for making tough moral judgments is emotion, not logic or analytical reasoning.

1. The volunteers thought about ethical dilemmas, then they went for a brain scan. These scans were studied by researchers.
2. The volunteers were thinking about ethical dilemmas while having their brains scanned. These scans were studied by researchers.

To me, it makes more sense to think that the scans happened while the volunteers were pondering instead of pondered. I can't seem to derive this meaning from OA.

PS: I got this question correct using the grammar rules and such. Just want to understand what this sentence is saying.

NunuBot Yes, meaning #2 is correct. That's how these kinds of scans work in real life, but we'd also need more clarification if #1 were intended. When would they have pondered these dilemmas? Have other people never pondered any ethical dilemmas? (Who are these thoughtless people?) At the very least, we'd want past perfect (had pondered) to make that meaning clear.

This leads us to the tense in the OA. Even though the main action is in the present perfect (Researchers . . . have found), it's fine to have the modifier "who pondered" occur in the past. These people pondered something while in the brain scan, and researchers have now found something as a result. We certainly could say "who were pondering." That might even be clearer. But the way the D uses "while pondering," it appears to modify the researchers' action, and C still has the potential for this confusion, so we have no valid option with "pondering" in it.
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Thanks for the confirmation!

During my first pass through, I eliminated all the choices with "pondered" because I thought it changed the meaning of sentence. But I found the options with "pondering" to be ambiguous as well, and I was torn between choosing the least ambiguous option...

Just wanted to confirm the OA is indeed ambiguous and i was able to identify the ambiguity. (part of the learning process!)