This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
The germ cells are derived from 
Select and explain. 
A. Yolk sac, B. Amnion, C. Germinal epithelium, D. Allantois
A: Yolk sac
Answer: A: Yolk sac 
Explanation: Germ cells developed from yolk sac epiblast(ectoderm). Ref: Human embryology; Inderbir Singh; Tenth edition