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: Pathology
[{'content': "Which of the following diseases of\tthe bone characteristically exhibits (in contrast to the other three conditions) a single lesion in a single bone? \nSelect and explain. \nA. Central giant cell granuloma, B. Osteopetrosis, C. Paget's disease of the bone, D. Polyostotic fibrous dysplasia", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]