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': "Keinbock's disease is osteochondritis of ? \nSelect and explain. \nA. Scaphoid, B. Lunate, C. Calcaneum, D. Tibial tuberosity", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Lunate", 'role': 'assistant'}]