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': 'Treatment of choice of flail chest chest is \nSelect and explain. \nA. External fixation of flail segment and mechanical ventilation, B. Strapping, C. O2 administration, D. Intrapleural local analgesia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]