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': 'A female wanted to have an emergency contraception after an unprotected intercourse. Which of these is NOT useful as an emergency contraceptive? \nSelect and explain. \nA. LNG IUD, B. Oral Mifepristone, C. Oral Levonorgestrel, D. Cu-containing IUD', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Post coital or emergency contraceptives are, Ethinyl oestradiol Conjugated estrogen Ethinyl oestradiol + Norgestrel Levonorgestrel Mifepristone Copper IUDs Ref: Textbook of Obstetrics by D.C. Dutta, 6th edition, Page 550.', 'role': 'assistant'}]