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
An example of antiprogesterone is: 
Select and explain. 
A. Gossypol, B. Atosiban, C. Clomiphene, D. Mifepristone
D: Mifepristone
Answer: D: Mifepristone 
Explanation: None