This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous system, Subject name: Physiology
Myelin in CNS 
Select and explain. 
A. Oligodendrocyte, B. Schwann cell, C. Astrocyte, D. Microglia
A: Oligodendrocyte
Answer: A: Oligodendrocyte 
Explanation: Oligodendrocytes - myelin formation in cnsSchwann cells - myelin formation in pns Ref: Ganong&;s review of medical physiology; 23rd edition; pg:80