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: Physiology
Sleep spindles and K-complexes are seen in which stage of sleep? 
Select and explain. 
A. REM, B. Stage 1 NREM, C. Stage 2 NREM, D. Stage 3 NREM
C: Stage 2 NREM
Answer: C: Stage 2 NREM 
Explanation: Ans. c. Stage 2 NREM