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': 'Which of the following medications would be prescribed most frequently to patients suffering from chronic atrial fibrillation ? \nSelect and explain. \nA. Lidocaine, B. Bretylium, C. Warfarin, D. Adenosine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]