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': 'Quindine is used to treat \nSelect and explain. \nA. Hypertension, B. Angina pectoris, C. Atrial fibrillation, D. Congestive heart failure', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]