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': 'Which of the following is an ionotropic receptor ? \nSelect and explain. \nA. Muscarinic cholinergic receptor, B. Nicotinic cholinergic receptor, C. Glucocorticoid receptor, D. Insulin receptor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]