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': 'In case of IVC obstruction the collaterals which open up are all except ? \nSelect and explain. \nA. Superior epigastric & inferior epigastric vein, B. Azygos & ascending lumbar vein, C. Superficial epigastric & iliolumbar vein, D. Lateral thoracic veins & preveebral vein', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Superficial epigastric pain drains into great saphenous vein. Iliolumbar vein drains into internal iliac vein,so these two do not form collateral between SVC & IVC as both of them will be ultimately drained into IVC.All other choices form collaterals between SVC & IVC.', 'role': 'assistant'}]