This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histamine, 5-HT and PGs, Subject name: Pharmacology
[{'content': 'Which of the following drugs can cause hypotension by release of histamine from mast cells? \nSelect and explain. \nA. Aspirin, B. Procaine, C. Morphine, D. Sulfadiazine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Basic drugs like morphine, d-TC(tubocurarine) and amphotericin B etc. act as histamine liberators and can cause acute reaction leading to itching and hypotension.', 'role': 'assistant'}]