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 union of: 
Select and explain. 
A. SMV & SV, B. SMV & IMV, C. IMV & SV, D. IMV + Hepatic vein
A: SMV & SV
Answer: A: SMV & SV 
Explanation: SMV & SV