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: Unknown
[{'content': 'Inflammable anesthetic agent - \nSelect and explain. \nA. Ether, B. Halothane, C. Cyclopropane, D. Trilene', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans-A', 'role': 'assistant'}]