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
In a middle-aged man the radiograph shows 'cotton- wool' appearance and blood investigation reveal an elevated alkaline phosphatase Levels. The tentative diagnosis is 
Select and explain. 
A. Paget's disease, B. Cherubism, C. Fibrous dysplasia, D. Osteogenesis imperfecta
A: Paget's disease
Answer: A: Paget's disease 
Explanation: None