This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Peripheral Arterial Occlusive Disease, Subject name: Surgery
[{'content': 'Best graft for femoropopliteal bypass - \nSelect and explain. \nA. Dacron, B. Saphenous vein, C. PTFE, D. None', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e.. Saphenous vein o Dacron is the femoral material for aortiliac work, it gives excellent results. For bypass in the femoropopliteal region, if autogenous vein is not available, PTFE or glutaraldehyde-tanned, Dacron-supported, human umblical vein may be employed.", 'role': 'assistant'}]