This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
[{'content': 'Which of the following medications would be prescribed most freequently to patients suffering from chronic atrial fibrillation? \nSelect and explain. \nA. Lidocaine, B. Bretylium, C. Warfarin, D. Adenosine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: (Ref: KDT 6/e p604) Patients of chronic atrial fibrillation are at high risk of developing thromboembolism. Oral anticoagulants are most frequently advised drugs in these patients to decrease the risk of this adverse effect.', 'role': 'assistant'}]