Explanation
In this vocabulary item, Sterile is the closest synonym of Barren, so option D is correct. The word Barren and the word Sterile share the same central sense in the context tested by the question, although usage, tone and grammatical form should still be checked before substituting one for the other. A synonym is not required to be identical in every possible sentence; it must preserve the intended meaning in the relevant context. Here, replacing Barren with Sterile keeps the core idea intact without reversing the tone or changing the action, quality or state expressed by the target word. The alternatives Deteriorate, Drain and Exonerate do not express the same central meaning as Barren. This distinction matters because competitive examinations often place one accurate synonym beside three familiar but contextually unsuitable words. To verify Barren independently, identify its part of speech, state a short definition, and place both Barren and Sterile in the same simple sentence. If the sentence retains its essential meaning and grammatical structure, the synonym relationship is supported. Learners should revise Barren together with Sterile, a brief usage cue and the contrasting distractors.