The behavior that is most clearly a response to a rhetorical situation is A. Organizing a speech by topic.
Rhetorical situations refer to the circumstances in which a speech or communication occurs, including the audience, purpose, and context. Organizing a speech by topic is a direct response to the rhetorical situation because it involves structuring the content of the speech in a logical and coherent manner that aligns with the purpose of the communication and the needs of the audience. By organizing the speech by topic, the speaker can effectively convey their message and engage the audience by presenting information in a systematic and organized way.