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': 'Relation of renal vein with aorta is - \nSelect and explain. \nA. Anterior , above Superior mesenteric artery, B. Anterior, below Superior mesenteric artery, C. Anterior, below Inferior mesenteric artery, D. Posterior, below Superior mesenteric artery', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Left renal vein passes behind and below the superior mesenteric artery, crossing in front of the aorta.', 'role': 'assistant'}]