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
K-complexes & Sleep spindles are seen in 
Select and explain. 
A. NREM 1, B. NREM 2, C. NREM 3, D. REM
B: NREM 2
Answer: B: NREM 2 
Explanation: Sleep spindles: Bursts of regular waves of frequency 13 -15 Hz
K- Complexes: High voltage spikes which are seen intermittently.
Both are seen in NREM2.