This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Arthritis, Subject name: Orthopaedics
[{'content': "A 60 year old man with history of long standing diabetes mellitus presents with painless, swollen right ankle joint. X-rays of the ankle show destroyed joint with large number of loose bodies. The most probable diagnosis is: \nSelect and explain. \nA. Charcot's joint, B. Clutton's joint, C. Osteoarthritis, D. Rheumatoid arthritis", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. A. Charcot's jointa. It is progressive destructive arthritis arising from loss of pain sensation and proprioceptionb. Joints lack normal reflex safeguard against abnormal stress injury.c. Causes- DM, Tabes dorsalis, Leprosy, syringomyelia, Myelomeningocele, Chronic alcoholism", 'role': 'assistant'}]