The spectacular disintegration of a comet last year in full

[Lisa]

GMAT PREP QUESTION

The spectacular disintegration of a comet last year in full view of ground- and space-based telescopes provided new insights into how comets form and may thus force a rethinking of the role of comets in the delivery of organic compounds to the evolving Earth.

A. The spectacular disintegration of a comet last year in full view of ground- and space-based telescopes provided new insights into how comets form and may thus force

B. The spectacular disintegration of a comet last year in full view of ground- and space-based telescopes, provided new insights into how comets form and thus possibly forcing

C. When a comet's spectacular disintegration occurred in full view of ground- and space-based telescopes last year, it provided new insights into how comets form and thus may possibly force

D. Last year, in full view of ground- and space-based telescopes, a comet's spectacular disintegration provided new insights into how comets form and thus possibly forcing

E. Last year, in full view of ground- and space-based telescopes, the spectacular disintegration of a comet has provided new insights into how comets form and may thus force




OA: A


Why is A preferred to D? What is grammatically wrong with D? Also, in answer B, is the comma before the word 'provided' grammatically incorrect, given how long the explanation before 'provided' is?

[kylo]

r u sure the OA is A.
sentence construction in A is pretty awkward.

i would have marked E as the answer.

In D, i think usage of "...forcing a rethinking .." would be incorrect.


Thanks!

[Lisa]

As per the GMAT Prep software the OA is indeed A. This question has been addressed elsewhere on this forum, but my question is with regards to the comma in answer choice B. I couldn't choose between A & B based on "may thus force" and "thus possibly forcing" but I found that the comma in answer choice B made the sentence flow better, so I chose B. Can Ron/Stavcey or any other verbal guru please elaborate on whether using a comma is appropriate and/or preferred in this question, or in other long sentences?

Thank you!

[RonPurewal]

I found that the comma in answer choice B made the sentence flow better

you found wrong.

if that's a proper transcription - with just that one comma - then that "sentence" is ungrammatical; it's not even really a sentence.

here's the good word:
"in full view of ground - and space-based telescopes" is a modifier. with such modifiers (occurring in the middle of the sentence), you have exactly 2 options:
* DON'T block the modifier off with commas. (this would be an "essential" modifier, one that must be retained for the sentence to be meaningful.)
* DO block the modifier off, with TWO commas, one on each side. (this would be a "nonessential" modifier, which can be omitted without semantic changes.)

those are all the options. you CANNOT have a comma on one side of the modifier but not on the other side.
(b) is thus ungrammatical, unless an additional comma is placed between "year" and "in".

--

"forcing" is a problem, because it's being placed in parallel to "provided" (the "and" is the parallel marker). in an "and" construction, you cannot have a participle (-ing) in parallel with a tensed verb.