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
Mechanism of action of clonidine is mediated by which of the following receptors? 
Select and explain. 
A. Alpha 1, B. Alpha 2, C. Beta 1, D. Beta 2
B: Alpha 2
Answer: B: Alpha 2 
Explanation: None