Which rhetorical device involves the repetition of a word or phrase at the beginning of successive clauses?

The correct answer is A, as anaphora is a rhetorical device characterized by the repetition of a word or phrase at the beginning of successive clauses or sentences. This technique is often used to create emphasis and rhythm in speech or writing, and it helps to reinforce an idea in the reader's or listener's mind.

For instance, in a famous speech, a speaker might repeat “I have a dream” at the start of several sentences to emphasize their vision and aspirations, thereby enhancing the emotional resonance of their message. Anaphora not only adds a lyrical quality to the language but also strengthens the argument being presented by creating a sense of consistency and unity.

The other options refer to different concepts: extrapolation is about deriving conclusions from data, aphorisms are concise, memorable expressions of a general truth, and argumentum ad hominem involves attacking the person making an argument rather than the argument itself. None of these involve the specific technique of repetition at the beginning of clauses, which is why they are not the correct answer.