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
According to WHO classification of ovarian tumours, Brenner tumor of ovary belongs to: 
Select and explain. 
A. Epithelial tumours, B. Sex cord stromal tumours, C. Germ cell tumours, D. Metastatic tumours
A: Epithelial tumours
Answer: A: Epithelial tumours 
Explanation: Cancer or Ovary