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': 'The most common anesthetic complication occurring within first 24 hours after surgery under general anesthetics is: \nSelect and explain. \nA. Hypertension, B. Renal failure, C. Atelectasis, D. Cardiac arrest', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]