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
The thresholds for permanent sterility in women for prepubeal exposure and premenopausal exposure conditions are 
Select and explain. 
A. 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
C: 12 Gy and 2 Gy, respectively
Answer: C: 12 Gy and 2 Gy, respectively 
Explanation: 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