This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pubey and Adolescent Health, Subject name: Pediatrics
[{'content': 'Menarche usually occurs how much time after thelarche? \nSelect and explain. \nA. 1 year, B. 2 years, C. 6 months, D. 4 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Menarche usually occurs 2-2.5 years after thelarche.', 'role': 'assistant'}]