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 step in management of head injury is: \nSelect and explain. \nA. Secure airway, B. I.V. mannitol, C. I.V. dexamethasone, D. Blood transfusion', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]