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': 'Early movement for surgery following ankylosis is \nSelect and explain. \nA. Harmful, B. Desirable, C. Unimportant, D. Indicated only when ankylosis is one sided', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]