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': 'Which of the following general anaesthetic agent has the least analgesic action? \nSelect and explain. \nA. N2O, B. Halothane, C. Ether, D. Propane', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Halothane is a potent inhalational anaesthetic but is not a good analgesic or muscle relaxant. It potentiates the effect of competitive neuromuscular blockers.', 'role': 'assistant'}]