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': 'Salbutamol is preferred over adrenaline in an asthmatic due to \nSelect and explain. \nA. β1 selectivity, B. β2 selectivity, C. α1 selectivity, D. None', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]