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 most common pure germ cell tumor of the ovary is: 
Select and explain. 
A. Choriocarcinoma, B. Dysgerminoma, C. Embryonal cell tumor, D. Malignant Teratoma
B: Dysgerminoma
Answer: B: Dysgerminoma 
Explanation: Dysgerminoma is the most common malignant germ cell malignancy of the ovary, accounting for about 40% of all ovarian cancers of germ cell origin. Ref: Multimodality Therapy in Gynecologic Oncology By BU. Sevin, 1996, Page 137