Aspeaker's interest in a topic corresponds to a) the speaker's level of knowledge b) the speaker's level of enthusiasm c) the speaker's understanding of audience d) the audience's interest in the topic

A speaker's interest in a topic corresponds to the speaker's level of enthusiasm.

Explanation:

The speaker is the one who participates in a dialogue, interacting directly with other people through the different types of communication. For a dialogue to occur fluidly it is necessary that the speakers have an interest in the topic being addressed. The interest of an interlocutor corresponds to his level of enthusiasm in the conversation, the more interest in the subject the more enthusiastic the speaker presents and the result of this is greater participation and exposition of ideas in the conversation.