As researchers continue to probe the highly expressive

[simplyjat]

As researchers continue to probe the highly expressive vocal and postural language of wolves, their close resemblance to dogs has become ever more striking.

(A) their close resemblance to dogs has become
(B) the closeness of their resemblance to dogs has become
(C) the close resemblance between them and dogs has become
(D) the close resemblance between wolves and dogs becomes
(E) the close resemblance of wolves with dogs becomes

OA D

[marustern]

A, B, and C are out because it is unclear whether 'their' or 'them' is referring to researchers or wolves.

We're left with 'resemblance between wolves and dogs' and 'resemblance of wolves and dogs'. Since we are comparing wolves and dogs and the similarities between the two animals, D is your best answer.

E is wrong because it is not a direct comparison of both wolves and dogs.

[simplyjat]

Is "resemblance between X and Y" an idiom?

[barron]

Only 'between X and Y' is an idiom

[nil4700]

As per the rules, a pronoun refers to the noun closer to it. Can't we take this for granted and say THEIR or THEM in the first three options are also in contention. If not are we just eliminating them for the sake the BEST answer?

[sibbineni]

resemblance between X and Y is the idiom

IMO D