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
[{'content': "Nonoxynol - 9 (marketed as 'Today') is a/an : \nSelect and explain. \nA. Hormonal contraceptive, B. Intrauterine contraceptive, C. Barrier ccntraceptive, D. Post - coital contraceptive", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Barrier ccntraceptive', 'role': 'assistant'}]