This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
[{'content': 'Which branch of poal vein is involved in chronic pancreatitis \nSelect and explain. \nA. Superior mesenteric vein, B. Inferior mesenteric vein, C. Left branch of poal vein, D. Splenic vein', 'role': 'user'}, {'content': 'Answer: D \nExplanation: ,', 'role': 'assistant'}]