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: Gynaecology & Obstetrics
All are tocolytics except: 
Select and explain. 
A. Ritodrine, B. Salbutamol, C. Isoxsuprine, D. Misoprostol
D: Misoprostol
Answer: D: Misoprostol 
Explanation: None