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: Physiology
[{'content': 'Function of microglia in CNS \nSelect and explain. \nA. Phagocytosis, B. Myelin synthesis, C. Fibrosis, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Microglia in CNS has phagocytic activity.', 'role': 'assistant'}]