This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gynaecological oncology, Subject name: Gynaecology & Obstetrics
According to WHO classification of ovarian tumors, Brenner's tumor of ovary belongs to : 
Select and explain. 
A. Epithelial tumours, B. Sex cord stromal tumors, C. Germ cell tumours, D. Metastatic tumours
A: Epithelial tumours
Answer: A: Epithelial tumours 
Explanation: - Brenner's tumor is epithelial ovarian tumor. - rare tumor and usually presents as a solid benign tumor. - occur in peri and post menopausal women. - islands of transitional epithelium in a fibrotic stroma giving it a solid appearance. Reference : textbook of gynaecology Sheila balakrishnan, 2nd edition, pg no:272