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
Selective Alpha 2 blocker is 
Select and explain. 
A. Tizanidine, B. Terazosin, C. Yohimbine, D. Dexmedetomidine
C: Yohimbine
Answer: C: Yohimbine 
Explanation: Yohimbine, idazoxan -selective alpha 2 blockers. Only two of them are present with no impoant clinical use. Ref: KD Tripathi.