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': 'The drug of choice for persistent unstable ventricular arrhythmia is- \nSelect and explain. \nA. Procainamide, B. Calcium gluconate, C. Amiodarone, D. Digoxin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: amiodarone is the drug of choice for persistent unstable ventricular arrythmias Ref Harrison 20th edition pg 1432', 'role': 'assistant'}]