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
Which of the following is a germ cell tumor? 
Select and explain. 
A. Brenner tumor, B. Granulosa cell tumor, C. Leydig cell tumors, D. Yolk sac tumor
D: Yolk sac tumor
Answer: D: Yolk sac tumor 
Explanation: Germ cell tumorsDysgerminomaEndodermal sinus tumor Embryonal carcinomaPolyembryomaChoriocarcinoma Immature teratoma Mature dermoid cyst with malignant transformationMonodermal and highly specializedStruma ovariiCarcinoidOthersReference: Novak's gynecology; 14th edition; Chapter 35; Uterine cancer