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
Radiation of 5 Gy will kill patients in: March 2013 (b, c, d, e, f) 
Select and explain. 
A. 1 day, B. 1 week, C. 2-3 weeks, D. 4-6 weeks
D: 4-6 weeks
Answer: D: 4-6 weeks 
Explanation: Ans. D i.e. 4-6 weeks