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
Drugs exhibiting first pass metabolism are all except one: 
Select and explain. 
A. Morphine, B. Nitroglycerine, C. Propranolol, D. Salicylates
D: Salicylates
Answer: D: Salicylates 
Explanation: None