During His Statistics Class This Morning, Stuart Was Completely Confused

During his statistics class this morning, Stuart was completely confused. He considered asking questions during the lecture, but because nobody else asked questions, he did not want to raise his hand and make a fool of himself in front of everyone. Stuart's failure to ask questions most likely stems from

A) diffusion of responsibility.
B) stimulus overload.
C) pluralistic ignorance.
D) audience inhibition.