This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Bruxism is ? 
Select and explain. 
A. Walking during sleep, B. Nocturnal enuresis, C. Grinding of teeth during sleep, D. Sleep apnoea
C: Grinding of teeth during sleep
Answer: C: Grinding of teeth during sleep 
Explanation: Ans. C. Grinding of teeth during sleep