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
On X-ray, joint swelling & intra-aicular 'calcification' appearance is seen in: September 2004 
Select and explain. 
A. Osteopetrosis, B. Paget's disease, C. Rheumatoid ahritis, D. Charcot's joint
D: Charcot's joint
Answer: D: Charcot's joint 
Explanation: Ans. D i.e. Charcot's joint