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
Ovarian tumours are commonly arise from: 
Select and explain. 
A. Stroma, B. Surface epithelium, C. Germinal epithelium, D. Endoderm
B: Surface epithelium
Answer: B: Surface epithelium 
Explanation: Epithelial tumors are derived from the ovarian surface epithelium. In general, epithelial tumors comprise 50-60% of all ovarian tumors but malignant epithelial tumors comprise 90% of all ovarian cancers.