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: Medicine
[{'content': 'Digoxin may be used in the treatment of- \nSelect and explain. \nA. Constrictive pericarditis, B. Cardiac tamponade, C. Atrial fibrillation, D. Diastolic failure', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]