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': 'Drugs exhibiting first pass metabolism are all except one: \nSelect and explain. \nA. Morphine, B. Nitroglycerine, C. Propranolol, D. Salicylates', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]