This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
[{'content': 'Which of the following drug is a long-acting beta-2 agonist \nSelect and explain. \nA. Albuterol, B. Salmeterol, C. Pirbuterol, D. Orciprenaline', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ref; KD Tripathi Pharmacology 7th edition(page no;223) Salmeterol is the first long-acting selective beta 2 agonist with a slow onset of action; used by inhalation on a twice-daily schedule for maintenance therapy and for nocturnal asthma, but not for acute symptoms. salbutamol can be used for acute symptoms', 'role': 'assistant'}]