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
The macrophage in the brain is - 
Select and explain. 
A. Schwann cells, B. Oligodendrocytes, C. Astrocytes, D. Microglia
D: Microglia
Answer: D: Microglia 
Explanation: None