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
Beta 2 agonist causes 
Select and explain. 
A. Mydriasis, B. Contraction of urinary spinctors, C. Vasoconstriction, D. Bronchial muscle relaxation
D: Bronchial muscle relaxation
Answer: D: Bronchial muscle relaxation 
Explanation: None