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
[{'content': 'Selective Alpha 2 blocker is \nSelect and explain. \nA. Tizanidine, B. Terazosin, C. Yohimbine, D. Dexmedetomidine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Yohimbine, idazoxan -selective alpha 2 blockers. Only two of them are present with no impoant clinical use. Ref: KD Tripathi.', 'role': 'assistant'}]