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
The drug available for the treatment of resistant cases of atrial fibrillation is? 
Select and explain. 
A. Amiodarone, B. Quinidine, C. Propranolol, D. Digoxin
A: Amiodarone
Answer: A: Amiodarone 
Explanation: Ans. is 'a' i.e., Amiodarone o Amiodarone is used to maintain sinus rhythm when other drugs have failed.