What is the sound of one hand clapping?

 I take attendance by having the students answer a question (previously 2016, 2017, 2019).

What is the sound of one hand clapping? Students mostly picked some popular onomatopoeias (or no): 

• clap (10)
• snap (6)
• no sound (3)

Then a lot of singletons:

• faint clap (1)
• snup (1)
• plap (1)
• tap (1)
• *pop* (1)
• plup (1)
• plap (1)
• hit (1)
• not possible (1)
• finger snap (1)

Two people were present in class but chose, as a way of expressing themselves, to checkmark next to their name on the sign-in sheet but leave the space for answering the question blank.

This post's theme word is gowpen (n), "two hands cupped together." Give me one gowpen of thoughtful questions, please.