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
The mu rhythm on EEG arises from? 
Select and explain. 
A. Primary visual area, B. Primary auditory area, C. Primary sensorimotor area, D. Primary olfactory area
C: Primary sensorimotor area
Answer: C: Primary sensorimotor area 
Explanation: mu(u) rhythm * 7 - 11 Hz normal waves. Seen during wakefulness and drowsiness. Arises from the Rolandic coex (primary sensorimotor coex) at rest. It can be unilateral, asynchronous and asymmetric.