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': 'What is the treatment of choice in severe flail chest? \nSelect and explain. \nA. IPPV, B. Strapping, C. Wiring, D. Nasal Oxygen', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]