This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'The most impoant structure involved in the development of inferior vena cava \nSelect and explain. \nA. Supra cardinal vein and sub cardinal vein, B. Persistence of Supra cardinal veins, C. Persistence of sub cardinal veins, D. Persistence of both supra and sub cardinal vein', 'role': 'user'}, {'content': "Answer: A \nExplanation: Inferior vena cava develop from sub cardinal vein especially the renal segment and the post renal segment. Right posterior cardinal vein contributes the inferior most component of IVC. Ref: Gray's 39e/p-210-220", 'role': 'assistant'}]