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 postoperative complications of tracheostomy are all, except \nSelect and explain. \nA. Apnoea, B. Haemorrhage, C. Pneumomediastinum, D. Tracheal stenosis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]