This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiotherapy, Subject name: Radiology
[{'content': 'The thresholds for permanent sterility in women for prepubeal exposure and premenopausal exposure conditions are \nSelect and explain. \nA. 1 Gy and 0.2 Gy, respectively, B. 6 Gy and 2 Gy, respectively, C. 12 Gy and 2 Gy, respectively, D. 0.5 to 2 Gy and 20 Gy, respectively', 'role': 'user'}, {'content': 'Answer: C \nExplanation: In women, radiation is highly effective at inducing permanent ovarian failure, but there is a marked age dependence insensitivity. The dose required to induce permanent sterility varies from 12 Gy (1,200 rad) prepubeal to 2 Gy (200 rad) premenopausal. Pronounced hormonal changes, comparable to those associated with the natural menopause, accompany radiation-induced sterilization in females.Reference: Eric J Hall Textbook of Radiobiology for Radiologist; 5th edition', 'role': 'assistant'}]