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 progesterone of choice for emergency contraception is aEUR' \nSelect and explain. \nA. Norethisterone, B. Medroxyprogesteronacetate, C. Levonorgestrel, D. Desogestrel", 'role': 'user'}, {'content': "Answer: C \nExplanation: Levonorgestrel [Ref: Dutra Obstetrics 6/e, p 549-550; S.K. Chaudhuri Feility Control 6/e, p 190-199; Novak's Gynaecology I4/e, p 283-385. Repeat from Nov 09 Q no.154", 'role': 'assistant'}]