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': 'Pungent volatile anesthetic agents are: \nSelect and explain. \nA. Halthane, B. Isoflurane, C. Sevoflurane, D. Desflurane', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Isoflurane', 'role': 'assistant'}]