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': 'Anaesthetic of choice for cardiac anaesthesia – \nSelect and explain. \nA. Isoflurane, B. Ketamine, C. Methoxyflurane, D. Halothane', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]