This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adrenergic 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: Ans. (B) Salmeterol(Ref: KDT 8th/e p243 & 5th/200)Salmeterol is a long acting b2 agonist whereas albuterol (salbutamol), pirbuterol and orciprenaline are short acting agents.', 'role': 'assistant'}]