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: Pharmacology
[{'content': 'Cardiac arrhythmias are most commonly seen during administration of \nSelect and explain. \nA. Thiopental, B. Halothane, C. Ethyl Ether, D. Nitrous oxide', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]