This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous system, Subject name: Physiology
Bruxism occurs in _______ phase of sleep 
Select and explain. 
A. ReM, B. NREM I, C. NREM II, D. NREM III
C: NREM II
Answer: C: NREM II 
Explanation: Bruxism can occur in any stage of sleep or at arousal from sleep. It is most common in stage N1 and N2 and least common during REM sleep Ref: guyton and hall textbook of medical physiology 12 edition page number: 721,722,723