ExplanationRecycle the clue and put enthusiasm in the blank. Both indifference and heedlessness are nearly the opposite of what you are looking for, so eliminate choices (B) and (E).
Neither cessation, which means stoppage, nor rhetoric, which is the art of effective or persuasive use of language, make sense in the blank, so eliminate choices (A) and (C). Both fervency and zeal can mean enthusiasm, so answer choices (D) and (F) give you appropriate, equivalent sentences.
Hence options D and F are correct
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