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: Anaesthesia
[{'content': 'Heavy smoker for elective hernia repair, smoking should be stopped before how much period? \nSelect and explain. \nA. 4 days, B. 10 days, C. 3-4 weeks, D. 6-8 weeks', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is \'d\' i.e., 6-8 weeksRef: Postgraduate anaesthesia p. 786\'Limited prospective data suggest that cessation for at least 6-8 weeks preoperative is necessary to decrease the incidence of pulmonary complication."', 'role': 'assistant'}]