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: Surgery
Preferred material for femoro popliteal bypass- 
Select and explain. 
A. Dacron, B. PTNE, C. Saphenous vein, D. Gortex
C: Saphenous vein
Answer: C: Saphenous vein 
Explanation: None