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: Physiology
[{'content': 'Cutaneous vasocontriction is mediated by \nSelect and explain. \nA. Sympathetic adrenergic nerves, B. Sympathetic cholinergic nerves, C. Parasympathetic cholinergics, D. Somatic nerves', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Noradrenaline acts on vascular smooth muscles to cause vasoconstriction. This is mediated by adrenergic sympathetic fibers.', 'role': 'assistant'}]