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
Antiarrhythmic drug is: 
Select and explain. 
A. Phentolamine, B. Phenobarbitone, C. Procainamide, D. Pentamidine
C: Procainamide
Answer: C: Procainamide 
Explanation: None