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
Vasomotor reversal of Dale is due to: 
Select and explain. 
A. α blocker, B. β–blocker, C. α and β–blocker, D. None
A: α blocker
Answer: A: α blocker 
Explanation: None