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': 'Hydatidiform - mole is characterized histologically by: \nSelect and explain. \nA. Hyaline membrane degeneration, B. Hydropic degeneration of the villous stroma, C. Non proliferation of cytotrophoblast, D. Non proliferation of syncytiotrophoblast', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]