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': 'Ovarian tumours commonly arise from : \nSelect and explain. \nA. Stroma, B. Germinal epithelium, C. Surface epithelium, D. None', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Surface epithelium', 'role': 'assistant'}]