This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth of the Fetus During Pregnancy, Subject name: Gynaecology & Obstetrics
[{'content': 'Fetus most radiosensitive at? \nSelect and explain. \nA. 8-15 weeks, B. 10-15 weeks, C. 15-20weeks, D. >20 week', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) 8-15 weeksRef.: Radiation Injury Prevention and Mitigation in Human by Kedar N. Prasad p-62', 'role': 'assistant'}]