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: Anatomy
[{'content': 'Basal lamina of blood vessel in CNS is secreted by \nSelect and explain. \nA. Endothelial cells, B. Oligodendrocytes, C. Microglia, D. Astrocytes', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]