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': 'Most radiosensitive tissue of body among the following is – \nSelect and explain. \nA. Bone marrow, B. Spleen, C. Kidney, D. Brain', 'role': 'user'}, {'content': "Answer: A \nExplanation: Bone & cartilage are radioresistant.\nEwing's sarcoma, seminoma and GI epithelium are highly radiosensitive.", 'role': 'assistant'}]