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': "In a middle-aged man the radiograph shows 'cotton- wool' appearance and blood investigation reveal an elevated alkaline phosphatase Levels. The tentative diagnosis is \nSelect and explain. \nA. Paget's disease, B. Cherubism, C. Fibrous dysplasia, D. Osteogenesis imperfecta", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]