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: Orthopaedics
[{'content': 'Increased bone density is not seen in \nSelect and explain. \nA. Osteopetrosis, B. Rickets, C. Hypervitaminosis A, D. Lead poisoning', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]