This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
Idazoxan is a (REPEAT) 
Select and explain. 
A. Alpha 1 agonist, B. Alpha 1 blocker, C. Alpha 2 blocker, D. Alpha 2 agonist
C: Alpha 2 blocker
Answer: C: Alpha 2 blocker 
Explanation: Yohimbine, idazoxan -selective alpha 2 blockers.