Question

Which of these nonverbal cues can give the impression that you are NOT confident? slouching business attire a comfortable amount of eye contact none of these

Answer 1

Slouching is a non-verbal cue that can give the impression that you are not confident. 

Answer 2

I would imagine "a comfortable amount of eye contact" would be a sign that you are confident, so that can be crossed out of the list.

"Business attire" gives off a professional vibe, which means if you happen to wear business attire, you're most likely serious about your topic and are confident about it, so that's also false.

Slouching could mean that you are not confident. When talking, you should stand straight up, slouching could give your audience the impression that you weren't well prepared for your topic or you're not confident about it.

So your answer should be "slouching" :)