Kindly suggest if there is a parallelism error as well in Option A.
Option A: Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.
I believe but is a parallel marker in the option and is followed by a sentence it was found by a joint Canadian-russian study....., is parallelism error also one ground to reject this answer option?

Kindly suggest if there is a parallelism error as well in Option A.
Option A: Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.
I believe but is a parallel marker in the option and is followed by a sentence it was found by a joint Canadian-russian study....., is parallelism error also one ground to reject this answer option?

GMATNinja Does the use of the pronoun "it" in A and B is an issue? Especially in A. Or is just a case of placeholder IT?

The "it" in choice (A) is certainly confusing.

Stripping out a prepositional phrase in (A), we have "... it was found to be both feasible as well as desirable." The "it" seems to be the thing that was found to be both feasible as well as desirable. And what was that thing? Air traffic routes over the North Pole? Well, in that case, we would need a plural pronoun ("they") and a plural verb ("WERE found to be...").

Maybe the "it" refers to "if those routes are opened to thousands more commercial planes a year"... but using "it" to refer to an "if" clause doesn't really make sense--is "if those routes are opened to thousands more commercial planes a year" the thing that's feasible and desirable??

Yes, there are times when the GMAT uses a "placeholder it" (also known as a "dummy pronoun" or a "non-referential pronoun" if you enjoy random terminology), but it's a rare thing, and you don't need to worry about it too much. For more on non-referential pronouns, check out this rant about licking frozen doorknobs.

For whatever it's worth: if we wanted to use "it" as a "placeholder", we would need something like, "... it was found THAT opening air traffic routes over the North Pole would be both feasible and desirable if..." Luckily, we don't have an option like that here, so it's definitely not a "placeholder".

I hope this helps!
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How I solve GMAT S C question in around 1 minute
It is possible! In order to nail an S C question in around 1 minute, two things are essential. We must have an in-depth knowledge of all GMAT S C error types tested, and we must approach a question with right strategy – your thought process.
Read this question:
Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian-Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.

A. Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian-Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.

B. Currently used by only two or three planes a day, a joint Canadian-Russian study has found that if air traffic routes over the North Pole are opened to thousands more commercial planes a year, it would be both feasible and desirable.

C. A joint Canadian-Russian study, finding it to be both feasible as well as desirable to open air traffic routes over the North Pole, which are currently used by only two or three planes a day, to thousands more commercial planes a year.

D. Although air traffic routes over the North Pole are currently used by only two or three planes a day, a joint Canadian-Russian study has found that opening those routes to thousands more commercial planes a year is both feasible and desirable.

E. With air traffic routes over the North Pole currently used by only two or three planes a day, opening those routes to thousands more commercial planes a year has been found by a joint Canadian-Russian study as both feasible and desirable

Some questions are partly underlined and others are fully underlined. Often fully underlined questions are more challenging because in a partly underlined question, we get some clues from non-underlined portion of the sentence which makes it easy to latch on to right answer.

First step is to read the entire sentence and try to get a sense of what the author is trying to tell us while simultaneously identifying errors if any. Remember, understanding overall meaning is critical. With practice, it is possible to understand meaning of a sentence even if there are multiple errors there. This is actually first thing that we have to master – understanding the meaning of a GMAT S C question with errors present.
Going back to the question, I have read the sentence and found two errors:
1.it was found by a joint Canadian-Russian study: GMAT prefers active voice, so this should be in active voice – Canadian -Russian study has found
2. both feasible as well as desirable: This is incorrect form. It should be – both feasible and desirable
Now, I have vertically scanned on the first error and eliminated C and E. Only B and D are using ‘Canadian – Russian study has found’. I have moved on and vertically scanned on the second error but couldn’t eliminate any because both are using -both feasible and desirable
So, I went back to the beginning of option B and found that it is illogically saying ‘Canadian – Russian study is being used by planes’
I won’t waste any time; I will immediately click option D and move on. Usually it is advisable to read our answer option back in to the sentence but here no back in to the sentence as the whole sentence is underlined. we can skip it.
Strategy slightly varies with question. Good luck!

Joseph Priestly
Sr. GMAT Instructor
Hyderabad
INDIA

Dear GmatNinja and Experts,

I am little confused over E to drop. Please help with the clarification.

----Quote------
Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.

E. With air traffic routes over the North Pole currently used by only two or three planes a day, opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable
----Unquote------

My assumptions
Part-1 With air traffic routes over the North Pole currently used by only two or three planes a day--- Simple present
Part-2 Opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable--- Present perfect

I think past event is missing here which is required to refer present perfect event.
Is this correct to drop E or please correct me.

Thank you!

I don't think we necessarily need a past event to refer to a present perfect event. The use of the present perfect here ("has been found") simply indicates that the action could have happened at any time in the past right up to the present moment -- and the action may have spanned any amount of time: days, weeks, months, years...

In this context, we know that it happened at SOME point in the past, but we have no idea when. The present perfect can work in situations like these (here's another example).

So I'm okay with using the present perfect in (E). But I'd prefer to see "... has been found TO BE both feasible and desirable" instead of "... has been found AS both feasible and desirable".

A bigger issue in (E) is the logic of the opening modifier, "With air traffic routes..."

Typically, when we open a sentence with a prepositional phrase, that phrase will modify the action performed in the following clause.

• "With $100 and case of beer, Tim headed to his daughter's dance recital." What did Tim head to his daughter's dance recital with? $100 and a case of beer.

But in choice (E), "With air traffic routes..." seems to modify how the "opening... has been found." The opening has been found alongside air traffic routes? The opening had been found by using air traffic routes? Neither interpretation makes sense. Because of the illogical modification, (E) is no good.

I hope that helps!
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A. The passive construction is wordy. "But it" was also bad English. The sentence is awkward and unclear.
B. The first part of the sentence has to subject and illogically modifying the joint Canadian and Russian Study. "It" at the beginning of the last part has no antecedent.
C. The joint Canadian and Russian Study has no verb. It also awkward and unclear.
D. The joint Canadian and Russian Study has verb " has found", It is perfectly saying two or three planes are currently using the north pole routes and also avoid reduntand "as well as" of the original sentence. [Correct]
E. Starting with "with is unidiomatic" and the passive form has been found is wordy.

Ans. D.
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