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
Which of the following is not a serotonin–norepinephrine reuptake inhibitor ? 
Select and explain. 
A. Venlafaxine, B. Duloxetine, C. Milnacipran, D. Tianeptine
D: Tianeptine
Answer: D: Tianeptine 
Explanation: None