The righty answer is D, at the beginning the narrator mentions how enthusiastic they are about the study of anatomy and paid lip service to the mismatch in time and the perception of it. At the end, as death is inevitable, the narrator urgers the reader to enjoy their lives, because it will eventually come to an end.
The answer is D. Nonfiction prose. It could not be A or B because it is not a poem, and it cannot be C because this is not fiction.
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