This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
Sleep spindles and K complexes occur in which phase of the sleep cycle? 
Select and explain. 
A. REM, B. Stage I, C. Stage II, D. Stage III
C: Stage II
Answer: C: Stage II 
Explanation: Stage II- Low voltage, mixed frequency background with sleep spindles (12-14 cps bursts) and K complexes (negative sharp wave followed by positive slow wave)