Although there have been numerous studies on the nature of the virus,

In option C, is the verb in the "while" clause corresponds correctly with the verb in the parallel clause? What has been omiited after "do not"?
(Please take into consideration that omission is acceptable, if the omitted part occurs in the corresponding parallel item.)

Moroever, you eliminated options stating that "ability" is not the scientists' concern - why not?

Ah! Thank you sayantanc2k for pointing out the error in my analysis. Really appreciate.

While some "do not develop" immunity is not parallel with Certain people "are able to" develop immunity.
The correct comparison would be, "Certain people "are able to" develop immunity while some people "are not able to" develop immunity.
What could be placed instead of "are not able to"? Some people "can not (develop immunity)", in that case (B) would be correct.

A parallel easier sentence would be-
Eg: Certain students are able to pass the GMAT with minimal effort, while some can not pass the GMAT even with full effort.
Here, if we used, "while some do not pass the GMAT", then it would seem that those who don't pass the GMAT do so out of their will. This is not the intended meaning, also, it does not make any sense. Here, "can not" can stand for "not able to". Because can is similar to able to. Example: He can do it = He is able to do it.

"Can" and "cannot" complement each other the best. Moroever "can" is better than "is able to" because it is more concise.

In that case, (E) is the best option among the given choices. And just solely on the basis of being concise, is it okay to eliminate (B)? Because the meaning is as clear and thorough in (B).

Although there have been numerous studies on the nature of the virus, the scientists cannot satisfactorily explain why certain vaccinated people can develop enough immunity to fight any further infection, while others do not.

A. cannot satisfactorily explain why certain vaccinated people can develop enough immunity to fight any further infection, while others do not -> I can see parallelism is lost, as we move from "can" to "do not". Incorrect.

B. are unable to explain satisfactorily why certain vaccinated people are able to develop enough immunity to fight any further infection, while others cannot -> Unable means, scientists cannot find the solution permanently. It is incorrect.

C. are not able to satisfactorily explain why certain vaccinated people are able to develop enough immunity to fight any further infection, while others do not -> not able means, scientists cannot find the solution temporarily. It is better than B. Further, I see parallelism error as we move from "are able" to "do not".

D. cannot explain satisfactorily why certain vaccinated people can develop enough immunity to fight any further infection, while others do not develop -> It has multiple errors, first, parallelism error as mentioned in A and why do we need "develop" in "while others do not develop". Incorrect.

E. cannot satisfactorily explain why certain vaccinated people can develop enough immunity to fight any further infection, while others cannot -> I see a parallel structure. I don't see any error further. Let's keep it.

So, I think E.

In option B there is a major grammatical problem: in the parallel structure, two verbs are compared: "are" and "cannot". The part "able to" is not part of the verb - "able" is an adjective outside the verb. Therefore the omitted part after "cannot" must be the same as that part after the verb "are", i.e. "able to": Thus the second item of the parallel structure becomes "cannot (able to....)", which is gramatically wrong. (In your analysis, you have considered that the second verb is "cannot develop" (a compound verb), but in the first part the word "develop" does not form a part of the verb.)

To maintain the correct parallelism in B, the ending should have been "are not" instead of "cannot" - "are able to" and "are not (able to)" would then be parallel.

OA not provided Bunuel generis

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The OA will be automatically revealed on Friday 22nd of April 2022 11:30:54 AM Pacific Time Zone