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': 'The drug in Norplant sub - dermal implant hormonal contraceptive is : \nSelect and explain. \nA. Norethisterone, B. Norethynodrel, C. Medroxy - progesterone, D. Levonorgesterol', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Levonorgesterol', 'role': 'assistant'}]