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
[{'content': 'Clonidine is used as an antihypertensive agent but if used as a fast intravenous injection, it can increase the blood pressure due to: \nSelect and explain. \nA. Stimulation of vasomotor center, B. Release of noradrenaline from adrenergic nerve endings, C. Agonistic action on vascular α2 adrenergic receptors, D. Cardiac stimulation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]