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
Which of the following is a very long acting Beta 2- agonist 
Select and explain. 
A. Salbutamol, B. Terbutaline, C. Indacterol, D. Salmeterol
C: Indacterol
Answer: C: Indacterol 
Explanation: Salbutamol, Terbutaline are short acting Beta 2 agonists.
Salmeterol, Formeterol are long acting Beta 2 agonists.
Indacterol, Carmoterol, Olodlaterol are very long acting Beta 2 agonists.