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': 'An example of covalent drug receptor interaction: \nSelect and explain. \nA. Noradrenaline binding to β1  adrenergic receptor, B. Acetylcholine binding to muscarinic receptor, C. Prazosin binding to α1   adrenergic receptor, D. Phenoxybenzamine binding to alpha adrenergic receptor', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Phenoxybenamine is an irreversible (covalent) antagonist at alpha receptors. All other drugs mentioned are reversibly interacting with their receptors.', 'role': 'assistant'}]