C is the correct answer. Made of wood.
C but could possibly be D
I believe its both but if I had to choose one I'd say
you should not chew gum in class because it's rude
Why:
It makes it look like your uninterested and not listening
If you have a cell phone yes, most students would use it for social media but it may also be used for school related topics.
Sit or stand attentively, responding with feedback when appropriate, watch your speaker, and maintain a quiet posture but also attentive
