This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
[{'content': 'Obstruction of inferior vena cava presents as \nSelect and explain. \nA. Paraumbilical dilatation, B. Thoracoepigastric dilatation, C. Esophageal varices, D. Hemorrhoids', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Inferior vena cava syndrome is a result of obstruction of the inferior vena cava. It can be caused by invasion or compression by a pathological process or by thrombosis in the vein itself.', 'role': 'assistant'}]