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 of 5 Gy will kill patients in: March 2013 (b, c, d, e, f) \nSelect and explain. \nA. 1 day, B. 1 week, C. 2-3 weeks, D. 4-6 weeks', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D i.e. 4-6 weeks', 'role': 'assistant'}]