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
Beta blockers are contraindicated in ? 
Select and explain. 
A. Sick sinus syndrome, B. Angina pectoris, C. Acute aoic dissection, D. Post MI
A: Sick sinus syndrome
Answer: A: Sick sinus syndrome 
Explanation: Ans. is 'a' i.e., Sick sinus syndrome