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
Which of the following drug is a long acting beta-2 agonist? 
Select and explain. 
A. Albuterol, B. Salmeterol, C. Pirbuterol, D. Orciprenaline
B: Salmeterol
Answer: B: Salmeterol 
Explanation: 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.