This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'WHO prognostic score for a high-risk GTN is \nSelect and explain. \nA. >= 6, B. >= 7, C. >= 10, D. >= 15', 'role': 'user'}, {'content': "Answer: B \nExplanation: Modified World Health Organization Prognostic Scoring System, as Adapted by FIGO, by which women whose score is 0-6 are Considered Low Risk (Requiring Single-Agent Chemotherapy) and score of 7 or more, High Risk (Requiring Multiagent Combination Chemotherapy)Scores0123Age<40>= 40----Antecedent pregnancyMoleAboionTerm--Interval months from index pregnancy<44-67-13>= 13Pretreatment serum hCG<10001000-1000010,000-100,000>100,000Largest tumor size --3-5 cm>= 5 cm--Site of metastasesLungSpleen, liverGastrointestinalLiver, brainNo. of metastases--1-45-8>8Previous failed chemotherapy----Single drug>= 2 DrugsReference: William's Obstetrics; 25th edition, chapter 20; Gestational trophoblastic diseases", 'role': 'assistant'}]