GRE Vocabulary Builder

Answer: Choice (D) is correct.

Superfluous means extra or excessive, beyond what is required, while obligatory means essential or mandatory. So, look for the answer pair that contains antonyms. Choice (A) contains synonyms. Precarious means unsteady or shaky, so eliminate that choice. Choice (B) also contains synonyms. One who is recalcitrant is rebellious or resistant. Sublime means lofty or magnificent, so eliminate that synonym set. The only choice that contains antonyms is choice (D). Pragmatic means sensible and realistic, not idealistic and impractical.