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 first and most important step in management of a case of trauma is: \nSelect and explain. \nA. Supply large amount of oxygen, B. Start intravenous infusion, C. Clearing the airway, D. Call ambulance', 'role': 'user'}, {'content': 'Answer: C \nExplanation: "Upon initial evaluation, ascertaining patency of the airway is of highest priority."', 'role': 'assistant'}]