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: Surgery
[{'content': "On X-ray, joint swelling & intra-aicular 'calcification' appearance is seen in: September 2004 \nSelect and explain. \nA. Osteopetrosis, B. Paget's disease, C. Rheumatoid ahritis, D. Charcot's joint", 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. D i.e. Charcot's joint", 'role': 'assistant'}]