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
All of the following drugs are oxytocics except: 
Select and explain. 
A. Oxytocin, B. Ergometrine, C. Prostaglandin, D. Orciprenaline
D: Orciprenaline
Answer: D: Orciprenaline 
Explanation: None