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
Which one of the following is a non - steroidal contraceptive : 
Select and explain. 
A. Ru - 486, B. Minipill, C. NET - EN, D. Centchroman
D: Centchroman
Answer: D: Centchroman 
Explanation: Centchroman