Here's the
official explanation provided by the GMAC for this question:
This sentence discusses evidence supporting a theory that a meteorite impact ignited global forest fires, and that these fires then contributed to many species' extinction. The sentence includes a complex series of nested noun phrases, resulting in potential confusion about which noun is modified by
ignited and which is the subject for
contributed. The underlined portion of the sentence must be worded to concisely and unambiguously resolve any such confusion. Idiomatically, the theory being discussed should be described as a theory
that certain events occurred, not a theory
of those events occurring.
Option A: The phrasing is convoluted and difficult to parse; the structure leaves unclear whether
ignited modifies
fires or
theory, and also whether
fires or
impact is the intended subject for
contributed. Idiomatically, the theory being discussed should be described as a theory
that certain events occurred, not a theory
of those events occurring.
Option B: Correct. This concise wording clearly and unambiguously shows that
ignited modifies
fires and also that
fires is the intended subject for
contributed. The phrase
theory that is idiomatically appropriate in the context
.Option C: Idiomatically, the theory being discussed should be described as a theory
that certain events occurred, not a theory
of the events
that occurred. This wording appears to indicate that the global wildfires had a theory. Otherwise, the wording is unnecessarily verbose.
Option D: In this context, the phrase
in support of is an unnecessarily wordy substitute for
supporting. The clauses following the first
that and the second
that should be grammatically parallel, but the first clause includes a subject and the second apparently does not. If the second
that is intended as a relative pronoun serving as the subject of the second clause, then its grammatical function is not parallel to the first
that's function, making the sentence structure confusing.
Option E: It is odd to say that a study of ancient clay deposits has provided evidence
of support for a theory–instead the evidence
is support for the theory. Idiomatically, the theory being discussed should be described as a theory
that a meteor impact ignited forest fires, etc., not a theory
of a meteorite impact that ignited forest fires.
The correct answer is B.
Please note that I'm not the author of this explanation. I'm just posting it here since I believe it can help the community.