This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Gynaecology & Obstetrics
[{'content': 'Spermicidal cream which is used in contraceptives? \nSelect and explain. \nA. Gossypol, B. Nonoxynol-9, C. Cent chroman, D. Clomiphene', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Spermicidal agents provide a physical barrier to sperm penetration and a chemical spermicidal action. Active ingredient is nonoxynol-9 or octoxynol-9. Spermicides must be deposited high in the vagina in contact with the cervix sholy before intercourse. Duration of maximal effectiveness is usually no more than 1 hour. Therefore, they must be reinseed before repeat intercourse.', 'role': 'assistant'}]