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': 'Radiation injury to the haemopoietic system of the bone marrow occurs when the whole body exposure ranges between: \nSelect and explain. \nA. 50-100 rads, B. 200-1000 rads, C. 1000-5000 rads, D. 10,000 rads to more', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]