This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Which of the following are seen in deep NREM sleep: 
Select and explain. 
A. Alfa waves, B. Beta waves, C. Teta waves, D. Delta waves
D: Delta waves
Answer: D: Delta waves 
Explanation: Delta waves are seen in deep sleep Beta waves are seen in active state Alfa waves are seen in patients with decreased attention Theta waves seen in case of drowsiness