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: Physiology
Not a site of hematpoiesis in fetus ? 
Select and explain. 
A. Kidney, B. Liver, C. Spleen, D. Yolk sac
A: Kidney
Answer: A: Kidney 
Explanation: Ans. is 'a' i.e., Kidney