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': "'Cotton-wool' appearance is seen in \nSelect and explain. \nA. Paget's disease, B. Osteosclerosis, C. Periapical cemental dysplasia, D. Ossifying fibroma", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]