Here's the
official explanation provided by the GMAC for this question:
This sentence compares bees' social structure to human social structures and to other social structures in the animal kingdom. The wording must clearly and concisely compare the bees' social structure only to other social structures, while indicating that the comparison as a whole involves all the social structures in the animal kingdom.
Option A: This absurdly compares the bees' social structure to
human beings in the animal kingdom, rather than to all the animal kingdom's social structures.
Option B: This absurdly compares the bees' social structure and other social structures in the animal kingdom to human beings themselves. Moreover, the use of
after does not adequately convey what is intended: that bees’ social structure is second in complexity only to humans’ social structures.
Option C: Correct. This clearly and concisely expresses the intended meaning that bees' social structure is the second-most elaborate in the animal kingdom. The pronoun
that refers back to
social structure.Option D: This absurdly compares the bees' social structure and other social structures in the animal kingdom to human beings themselves, rather than to human beings' social structures.
Option E: The phrase
disregarding that of is an unnecessarily wordy and unclear substitute for
next to. It confusingly suggests that the bees' social structure itself is disregarding humans' social structure. Furthermore,
in the animal kingdom may be misread as modifying either
human beings or
that of human beings, rather than
social structure. The correct answer is C.
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.