This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vascular surgery, Subject name: Surgery
[{'content': 'Most commonly varicose veins are seen in \nSelect and explain. \nA. Sho saphenous vein, B. Long saphenous vein, C. Popliteal vein, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The usual distribution of varicose veins is below the knee in branches of the greater saphenous system.', 'role': 'assistant'}]