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
The commonest type of ovarian tumour is : 
Select and explain. 
A. Dermoids, B. Cystadenoma, C. Fibroma, D. Cystadenocarcinoma
B: Cystadenoma
Answer: B: Cystadenoma 
Explanation: Cystadenoma