Here's the
official explanation provided by the GMAC for this question:
The wording of the original sentence makes it clear that at the time when the developer’s plans were approved, only eight Revolutionary War battlefields remained undeveloped and that the one for which the development plans were approved was one of those eight. In each of the other versions, the placement of
only or the form and position of the verb
remain/remains/remaining make the intended meaning less clear.
Option A: Correct. The verb forms and the relative positions of modifiers allow this to convey a clear, coherent meaning. The past perfect
had remained is the appropriate verb form for describing a situation that lasted up until the past event the sentence's main clause describes.
Option B: One of eight of the only is awkward, indirect, and unclear. It confusingly suggests that more than eight Revolutionary War battlefields remained undeveloped.
Option C: The relationship of
remains to the phrase
undeveloped Revolutionary War battlefields makes this unclear and potentially misleading. The singular verb
remains suggests that the relative pronoun
that is also singular (as the subject of the verb) and that its antecedent is
one, also singular. This answer choice appears to say, somewhat oddly, that there were only ever seven other undeveloped Revolutionary War battlefields and that those others no longer exist. However, the intended meaning is probably that only these eight remained undeveloped in June of 1989.
Option D: Given the position of
only in this phrase, the author’s point in using that word, rather than merely saying that this was one of the eight Revolutionary War battlefields that remained undeveloped is unclear. It could, for example, convey an intention to downplay the importance of losing a historical site to development. Furthermore, the time reference in
to remain undeveloped is unclear; it could be interpreted as suggesting illogically that the battlefield is to remain undeveloped after the houses are built.
Option E: Given the position of
only in this phrase, the author’s point in using that word, rather than merely saying that this was one of the eight Revolutionary War battlefields that remained undeveloped is unclear. It could, for example, convey an intention to downplay the importance of losing a historical site to development. The time reference is also unclear: does the sentence mean that the eight battlefields still remain undeveloped, or only that they remained undeveloped in June of 1989?
The correct answer is A.
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.