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: Anatomy
Poal Vein is formed by the union of? 
Select and explain. 
A. Superior Mesenteric and Inferior Mesenteric Veins, B. Superior Mesenteric and Splenic Veins, C. Superior Mesenteric And left renal vein, D. Inferior Mesenteric and Splenic Vein
B: Superior Mesenteric and Splenic Veins
Answer: B: Superior Mesenteric and Splenic Veins 
Explanation: Superior Mesenteric and Splenic Veins "The hepatic poal vein, formed by the union of the superior mesenteric and splenic veins, is the main channel of the poal venous system, which collects blood from the abdominal pa of the alimentary tract, pancreas, spleen, and most of the gallbladder and carries it to the liver" Major Vessels of the Hepatic Poal System