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': 'Which one of the following is a non - steroidal contraceptive : \nSelect and explain. \nA. Ru - 486, B. Minipill, C. NET - EN, D. Centchroman', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Centchroman', 'role': 'assistant'}]