This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bronchopulmonary Segments, Embryonic veins, Subject name: Anatomy
The poal vein is derived from which of the following? 
Select and explain. 
A. Vitelline veins, B. Umbilical veins, C. Anterior cardinal veins, D. Posterior cardinal veins
A: Vitelline veins
Answer: A: Vitelline veins 
Explanation: The poal vein is derived from :- Major contribution from Right vitelline vein Minor contribution from left vitelline vein Dorsal anastmosis between left and right vitelline vein (NOTE - vitelline of each side are connected to each other by proximal , middle and distal anastmosis )