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': 'Contraindicated in head injury – \nSelect and explain. \nA. Halothane, B. Ketamine, C. N2O, D. Propofol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]