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': 'Ether is not used in modern surgical practice, because it is – \nSelect and explain. \nA. Highly explosive, B. Poor anaesthetic, C. Expensive, D. Complicated apparatus needed', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ether is highly inflammable and explosive.', 'role': 'assistant'}]