Final answer:
An individual fulfills the rhetorical proof of ethos to be a competent, trustworthy, and dynamic speaker. Therefore, the correct option is B ethos
Step-by-step explanation:
To be a competent, trustworthy, and dynamic speaker, an individual is fulfilling the rhetorical proof of ethos. Ethos is the presentation of a believable, authoritative voice that elicits an audience's trust. It involves establishing the speaker's credibility and qualifications on the subject. By being competent and trustworthy, the speaker appeals to the audience's ethics and builds credibility, which is essential for effective communication.