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: Unknown
[{'content': 'In autonomic nervous system, parasympathetic outflow is mainly by \nSelect and explain. \nA. Cholinergic, B. Adrenergic, C. Noradrenergic, D. Histaminergic', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]