Eye contact, voice, intonation, body language, and emotions are correct.
Explanation:
A nonverbal behavior is the one that communicates something without the use of language and they can help or bother communication. If Ronald wants to keep public's attention, it is important to make eye contact, so the speaker and the audience create a kind of bond. Voice and intonation are also factors that can help Ronal create trust, he should sound convinced and use his voice to emphasize specific parts of his speech; body language can also help this, since he could express more emotions in the important parts, guiding the audience's attention to things that are important for his presentation and project, so he can create that desired trust.
