Answer:
D. The power of self-confidence.
Explanation:
The "theme" refers to the "subject" of the speech. It should be related to the speakers "personal interest." For example, if his theme is about "The power of self-confidence," he will be telling the people why he thinks that self-confidence is important for a person in a society. Since speech is all about "expressing one's self," such topic will allow the speaker to delve on the theme in relation to his audience.
So, this explains the answer.
