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': 'Double contrast phase contrast arthroscopy is used for analysis of: \nSelect and explain. \nA. Disc., B. Joint space., C. To treat dislocation., D. None.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]