Answer:
D. Knowledge about the topic.
Explanation:
Audience analysis is one of the crucial elements to consider which includes several elements like the audience's expectations, knowledge, and attitude towards the topic, audience size, demographics, etc. Yet the most significant factor for Dimitri to consider would be the "knowledge about the topic" as the speaker is required to have a fair idea of what the listeners already know. The speaker should never under/overestimate the speaker's intellect as it may mislead them and consequently, the audience may lose interest or misinterpret the speaker's intellectual ability. Thus, this is of utmost concern as if the speaker has sound expertise on the topic, the size, age membership, attitude towards the speaker would not matter that much as their intellect and wisdom would eventually convince them to believe and applaud the speaker.
