The amazing thing is knowing the use of metaphor.

Concept: In this kind of paraphrase question, the task is to find the option whose wording keeps the same sense as the original, not just similar-looking words. English nouns commonly paired with "knowing" carry different senses: "art of X" is the natural way to describe skilful practice or use of X, "command of X" describes fluent mastery (usually of a whole language), and "knowledge of X" means only being informed about X.

Application: The given sentence praises knowing the "use" of metaphor — that is, being able to skilfully employ it. Among the given choices, "art of metaphor" is the closest and most natural fit for that sense of skilful use, so it preserves the original meaning best. "Knowledge of metaphor" weakens the meaning to mere awareness, and "command of metaphor" borrows a collocation normally reserved for command of a whole language, which does not fit a single figure of speech such as metaphor.

Cross-check: Testing the same nouns against familiar idioms confirms the pattern — we say "the art of persuasion" or "the art of conversation" for a practised skill, but "a good command of English" for language fluency and "knowledge of a subject" for plain information. None of the command/knowledge substitutes describes the practical "use" the original sentence is praising.

Contrast of the other phrasings:

- "Knowing the knowledge of metaphor" is also awkwardly repetitive (knowing the knowledge) and reduces the sentence to bare awareness of metaphor, not skill in using it.

- "Knowing the command of metaphor" stretches a language-fluency idiom onto a single figure of speech, which is not a natural English collocation.

- "None of the above" fails because one listed phrasing does keep the original sense.

So, among the given choices, the sentence that most faithfully keeps the original meaning is: "The amazing thing is knowing the art of metaphor."