This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
[{'content': 'Posterior relation of poal vein \nSelect and explain. \nA. 1st pa of duodenum, B. Hepatic aery, C. Bile duct, D. IVC', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The poal vein usually measures approximately 8 cm in adults. It originates behind the neck of the pancreas and is classically formed by the confluence of the superior mesenteric and splenic veins. ref - BDC 6e vol2 pg282 , researchgate.net', 'role': 'assistant'}]