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: Radiology
[{'content': 'Fixed post mitotic cells are: \nSelect and explain. \nA. Spermatocytes, B. Fibroblasts, C. Endothelial cells, D. Muscle', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]