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: Gynaecology & Obstetrics
[{'content': 'Gonadotropin levels decline to prepubertal levels by age \nSelect and explain. \nA. 6 month to 1 year of age, B. 1 year to 2 years of age, C. 2 years to 3 years of age, D. 3 years to 4 years of age.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Gonadotropin levels gradually decline to reach prepubertal levels by age 1 to 2 years.', 'role': 'assistant'}]