OFFICIAL EXPLANATION



THE PROMPT




THE OPTIONS


• the subject of the sentence, the Rosetta Stone, is singular, and does not agree with the plural verb were
Eliminate A

• this option is an adjective phrase that describes the noun Rosetta Stone, but
-- because the phrase is placed right after Greek, the phrase illogically and incorrectly modifies Greek
-- according to the "Touch Rule" of noun modifiers, the modifier must be placed as close as possible to the noun it modifies.
This option gives us a "misplaced modifier."

• the sentence is disjointed because the phrase is just "stuck on" to the end without transition (e.g. a conjunction and a verb)
Eliminate B

• the antecedent of which is either the word Greek or potentially ambiguous.
The first possibility is illogical and the second is unacceptable.
• be careful - GMAC has been inconsistent about whether which can be far away from its logical antecedent.
-- true pronoun ambiguity is rarer than people believe
-- GMAC seems to be more persnickety about the pronoun which than it is about the pronoun it
-- a pronoun must have only one logical antecedent.
By that definition, this option is acceptable.
The word which can refer to relatively far away nouns.
But an acceptable answer does not mean the best answer.
KEEP, but tentatively, and look for a better answer

• this option is better than option C:
Option D creates a parallel compound predicate (see Notes):
. . . the Rosetta Stone was inscribed . . . and was instrumental
Eliminate option C, KEEP D

• this option is a hot mess
• in its deciphering (ouch)? No. The Rosetta Stone did not itself decipher ancient Egyptian hieroglyphs.
• the word which cannot modify the entire previous clause; which must refer to a noun, and in this option which is trying to refer to the whole idea that the Rosetta Stone was instrumental
• "which helped"? Helped whom? Helped what?
-- the verb help is transitive and requires an object.
Eliminate E.

The best answer is D

Notes

GMAC frequently tests the word which.
Some of you have been taught that COMMA + WHICH modifies only the immediately preceding noun or main noun in a noun phrase.
Not always.
True, it is rare for the antecedent of which to be far away from which, but the antecedent can be fairly far away.

Compound predicate?

Don't worry about the jargon.
Just understand what is supposed to happen: namely, that when a subject is connected to a compound predicate, the subject is not repeated, a pronoun is not inserted, and a comma is not inserted before the second verb.

A predicate is the part of the sentence that contains the verb or verb phrase.

Two verbs can share the same subject.
Stated differently, one subject can be followed by two verbs.
One subject can perform two actions (or, in this case, one subject can have two actions performed upon it).
In (D), the single subject, Rosetta Stone, is connected to two parallel verbs: was inscribed and was instrumental.

When we have a compound predicate, almost always we do not insert a comma before the second verb and we do not repeat the subject or its pronoun.
Note the qualification, almost always.

The following sentences would probably be incorrect on the GMAT.
Probably wrong: Aisha walked to the store, and bought an apple.
(no comma before the second verb in a compound predicate)
Probably wrong: Aisha walked to the store and she bought an apple.
(do not repeat the subject or a pronoun for the subject)
Probably wrong: Aisha walked to the store, and she bought an apple.
(do not commit both errors)

This approach is standard in formal written English.
We want to keep the subject as connected to its verbs as possible. A comma before the second verb "interrupts" that connection.
We want to be concise. Repeating the subject (or a pronoun for the subject) is needlessly lengthy.

I highlight this issue because I want you to be suspicious of sentences that do not follow the guidelines I've laid out.
Most of the time they are incorrect.
More importantly, most of the time these sentences will contain another error.

One very hard official question tests these rules, and the wrong answer contains no other error.
Spoiler alert: links are to an official question.
That question is here.
I explained the official question's answer in this post, here.

COMMENTS

thenikhilseth and 1473 , welcome to SC Butler.

I like to see your thought processes laid out.
In addition, posting answers is good practice: if you can explain a concept, you will not make many errors when you encounter it.
And you have to reason "out loud."
Having to reason and to explain are good practice for the test.

I am glad to see more and more newcomers.
And if more of you are kinda peeking in here and there, I invite you to post.
This site is a community.

I often give kudos for incorrect answers as long as the reasoning is coherent, however inaccurate an assumption may have been.
Kudos to all.

My answer is d because it is the only option that correctly references the roestta stone in the singular (this narrows it down to d or e) and references its use to the scientists in deciphering hieroglyphics (as opposed to option eimplying it did the deciphering itself).

Posted from my mobile device

The reason c is incorrect is because the 'which' leads to a confusion in understanding whether the remaining part of the sentence refers to the Rosetta stone or the Greek it is inscribed with.

Posted from my mobile device

A) and were instrumental in helping scholars decipher the hieroglyphs used by ancient Egyptians- Incorrect

Rosetta stone is a singular noun

B) instrumental in helping scholars decipher the hieroglyphs that had been used by ancient Egyptians- Incorrect

1)This option is not completing the statement.
2) Secondly, it is conveying that 2 languages are instrumental rather than Rosetta stone

C) which was instrumental in helping scholars decipher the hieroglyphs used by ancient Egyptians- Incorrect

Which is referring to Greek language

D) and was instrumental in helping scholars decipher the hieroglyphs used by ancient Egyptians- Correct

Properly conveying the intended meaning that Rosetta stone is written in 2 languages and is instrumental....

E) and was instrumental in its deciphering of ancient Egyptian hieroglyphs, which helped- Incorrect

Discovered by a French soldier in 1799, the Rosetta Stone was inscribed with three distinct scripts in two languages, Egyptian and Greek, and were instrumental in helping scholars decipher the hieroglyphs used by ancient Egyptians.

Since we have "and" the verb "were instrumental" has to go with the subject "Rosetta Stone" which is singular and wouldn't make sense as an independent idea per my understanding.

Correct - instrumental - adjective modifying scripts in two languages. Past Perfect "had been" is correct as well as the hieroglyphs were used earlier and then deciphered

"which" - modifying scripts which is plural. Hence can not go with "was" - SV Disagreement

"and was instrumental" goes with "Rosetta Stone". But this idea is acting as an independent idea that doesn't create a link between the inscriptions and the deciphering of the hieroglyphs.

Same as D, moreover this one has too many issues

I went with B. "Instrumental" is an adjective modifying the "3 scripts in 2 languages" which in turn actually helped the scholars decipher. Comma pair can be taken off and the sentence would still stand correct grammatically.

From what I understand Rosetta Stone was discovered by French and there were inscriptions on the stone in different languages and that these languages helped or were instrumental in helping scholars decipher the XYZ.

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The official explanation is here

Dear Friends,
Here is a detailed explanation to this question-



A: This answer choice uses the plural verb "were" to refer to the singular noun "Rosetta Stone". Thus, this answer choice is incorrect.

B: This answer choice incorrectly modifies the noun phrase "two languages", rather than the noun "Rosetta Stone", with the phrase "instrumental in helping..."; the stone, not the languages, was instrumental to the scholars' efforts. Thus, this answer choice is incorrect.

C: This answer choice incorrectly modifies the noun phrase "Egyptian and Greek", referring to the ancient Egyptian and Greek languages, with the phrase "which was instrumental...". As mentioned above, it was the stone, not the languages, that was instrumental to the scholars' efforts. Thus, this answer choice is incorrect.

D: This answer choice preserves the meaning of the sentence and maintains proper subject-verb agreement. Thus, this answer choice is correct.

E: This answer choice suffers from a meaning-related error; E omits the word "scholars" and uses the phrase "its deciphering", implying that the Rosetta Stone itself took the action of deciphering. E also modifies the noun "hieroglyphs" with the phrase "which helped", further altering the meaning of the sentence. Thus, this answer choice is incorrect.

Hence, D is the best answer choice.

Please note that in Option B, the phrase "instrumental in helping" applies to the noun "languages" because the noun phrase "Egyptian and Greek" is presented between two commas.

To understand the concept of "Extra Information Between two Commas on GMAT", you may want to watch the following video (~1 minute):



To understand the concept of "Use of Which, Who, Whose, and Where on GMAT", you may want to watch the following video (~1 minute):



All the best! Experts' Global Team
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