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
[{'content': 'Maximum duration of sleep is spent in \nSelect and explain. \nA. NREM 1, B. NREM 2, C. NREM 3, D. REM', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Maximum duration is spent in\xa0NREM 2.', 'role': 'assistant'}]