This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
[{'content': 'In the treatment of severe bradycardia, all of the following can be the best modality of treatment except - \nSelect and explain. \nA. Atropine, B. Pacing, C. Isoproterenol, D. Diltiazem', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Diltiazem Bradycardia", 'role': 'assistant'}]