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
[{'content': 'Poal vein begins at the level of which veebra? \nSelect and explain. \nA. L2, B. L4, C. L5, D. None of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: The poal vein begins at the level of the second lumbar veebra and is formed from the convergence of the superior mesenteric and splenic veins. It is 8 cm long and lies anterior to the inferior vena cava and posterior to the neck of the pancreasRef: Gray's anatomy 40th edition, Chapter 85.", 'role': 'assistant'}]