Final answer:
The term for expressing strong emotions or arguments in a powerful, persuasive manner is 'eloquent'. An eloquent person speaks effectively and convincingly. The term for a disease constantly present in a population is 'endemic', but in the context of the student's question, 'eloquent' is the correct answer.
Step-by-step explanation:
The term that means expressing strong emotions or arguments in a powerful, fluent, and persuasive manner is B. Eloquent. An eloquent individual is able to convey their feelings or thoughts very effectively and convincingly. This characteristic often results in a significant impact on the audience.
On the other hand, the term endemic refers to a disease that is constantly present in a particular population or area. It's important not to confuse these terms as they relate to different concepts. The correct answer to the student's question is eloquent, which is option B.