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': 'Left renal vein crosses aoa: \nSelect and explain. \nA. Posterior at level of superior mesenteric aery, B. Anterior above the level of superior mesenteric aery, C. Anterior below the superior mesenteric aery, D. Anterior below the inferior mesenteric aery', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e., Anterior below the superior mesenteric aery', 'role': 'assistant'}]