Which of the following best defines "anaphora"?

Anaphora is defined as the repetition of a word or phrase at the beginning of successive clauses or sentences. This literary device is often used to create emphasis, rhythm, and a sense of urgency in writing. By employing anaphora, a writer can draw attention to important ideas and evoke strong emotional responses from the audience. A well-known example of anaphora is Martin Luther King Jr.'s "I Have a Dream" speech, where the repeated phrase enhances the powerful message he conveys.

The other choices describe different rhetorical devices that do not align with the definition of anaphora. Repetition at the end of sentences pertains to the concept of epistrophe, while contrasting ideas relate to antithesis. A technique for building conflict is more general and could involve several literary strategies, none of which specifically describe the mechanism of anaphora. Hence, the correct definition is indeed the repetition at the beginning of successive clauses, which serves to unify and underscore the points being made.