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': 'Atypical endometrial hyperplasia undergoes malignant transformation in : \nSelect and explain. \nA. 10%, B. 25%, C. 45%, D. 70%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 25%', 'role': 'assistant'}]