This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sleep Disorders, Subject name: Psychiatry
[{'content': 'The EEG recorded shown below is normally recordable during which stage of sleep? \nSelect and explain. \nA. Stage I, B. Stage II, C. Stage III, D. Stage IV', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Following are seen in Stage II of NREM sleep: 1. Sleep spindles( burst of regular waves, 13- 15 Hz , 50 micro volt) 2. K complexes - High voltage spikes, seen intermittently', 'role': 'assistant'}]