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': '% of ovarian tumours of non epithelial origin in childhood is : \nSelect and explain. \nA. 20%, B. 30%, C. 40%, D. 50%', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 50%', 'role': 'assistant'}]