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': 'Drug of choice for paroxysmal supraventricular tachycardia (PSVT) is: \nSelect and explain. \nA. Verapamil, B. Digitalis, C. Quinidine, D. Diphenylhydantoin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]