This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
[{'content': 'Which of the following general anaesthetics has poor muscle relaxant action? \nSelect and explain. \nA. Ether, B. Nitrous oxide, C. Halothane, D. Isoflurane', 'role': 'user'}, {'content': 'Answer: B \nExplanation: (Ref: KDT 6/e p371) Nitrous oxide is not a complete anaesthetic (MAC 104%). It is a good analgesic but poor muscle relaxant.', 'role': 'assistant'}]