GRE Vocabulary Builder

Answer: Choice (D) is correct.

In the first half of the analogy, perfunctory and obligatory are synonyms that describe doing something in an automatic or dutiful way. So, look for the answer choice that contains synonyms. In choice (A), susceptibility means that one is vulnerable or predisposed, while imperviousness means that something that is resistant. Therefore, eliminate choice (A). In choice (B), tractable means easily controlled or guided, not disobedient, so eliminate choice (B). In choice (C), someone who is vindictive has a desire for revenge, while someone who is compassionate is kindhearted and forgiving, so eliminate choice (C). In choice (D), pusillanimous means timid or cowardly, so that is the correct choice.