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': 'Which of the following β-blocker is safe in asthma \nSelect and explain. \nA. Celiprolol, B. Timolol, C. Carveidilol, D. Labetalol', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Celiprolol is a selective\xa0β1 blocker (cardioselective), has no action on\xa0β2 receptors present on bronchial smooth muscle. Hence it is safe in asthma.', 'role': 'assistant'}]