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': 'Beta blockers are contraindicated in ? \nSelect and explain. \nA. Sick sinus syndrome, B. Angina pectoris, C. Acute aoic dissection, D. Post MI', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Sick sinus syndrome", 'role': 'assistant'}]