This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
[{'content': "Which Drug is contraindicated in prince metal's angina is: \nSelect and explain. \nA. Nifedipine, B. Amyl nitrate, C. Propranolol, D. Calcium channel blocker", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans: c', 'role': 'assistant'}]