This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fertilization and Development of Embryo, Subject name: Anatomy
Primordial Germ cell develops from? 
Select and explain. 
A. Chorion, B. Amnion, C. Yolk sac, D. Cord blood
C: Yolk sac
Answer: C: Yolk sac 
Explanation: ANSWER: (C) Yolk sacREF: Embryology by Ramesh Mathur,Meenakshi Mehta page-38, Color atlas of embryology by Ulrich Drews page 15"In mammalian embryo, including man, the primordial germ cells apparently arise from the en do dermal layer near the yolk sac"'Germ cells arise in the embryonic yolk sac, differentiate in the gonads and pass on the genome as gametes"