This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General surgery, Subject name: Anatomy
Best graft for infra inguinal approach bypass 
Select and explain. 
A. Dacron, B. PTFE, C. Polyester, D. Autologous vein
D: Autologous vein
Answer: D: Autologous vein 
Explanation: The great saphenous veins should be used preferentially in all bypasses, especially in those reconstructions using below-knee popliteal and small tibial aeries as the distal target vessels. PTFE grafts can be used for bypasses to above-knee popliteal aerial segments with satisfactory patency rates. Ref: Sabiston 20th edition Pgno: 1774