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': 'Medication used in treatment of idiopathic central precolcious puberty is: \nSelect and explain. \nA. Exogenous gonadotrophins, B. Ethinyl estradiol, C. Gn RH analogues, D. Ethinyl estradiol', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]