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: Surgery
[{'content': 'The latent period in distraction osteogenesis is \nSelect and explain. \nA. 4-6 weeks, B. 5-7 days, C. 6-8 months, D. 4 months', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]