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: Pathology
It is a type of nerve cell that protects CNS from infection and become phagocytic in response to inflammation 
Select and explain. 
A. Schwann cells, B. Ependymal cells, C. Microglia, D. Astrocytes
C: Microglia
Answer: C: Microglia 
Explanation: C: Microglia helps remove bacteria and cell debris from the CNS.
A: Schwann cells form myelin sheaths around axons, or enclose unmyelinated axons in the peripheral nervous system.
B: Ependymal cells line ventricles of the brain, circulate cerebrospinal fluid; some form choroid plexuses, which produce CSF.
D: Astrocytes serves as the major supporting tissue in the CNS and contribute to the blood-brain barrier.