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: Anatomy
True about the anatomy of great saphenous vein: 
Select and explain. 
A. Stas as a continuation of medial marginal vein, B. Ends of femoral vein 2.5 cm below the inguinal ligament, C. There are 2 - 5 valves below the knee., D. Ascends 2.5 - 3 cm behind tibial malleolus
A: Stas as a continuation of medial marginal vein
Answer: A: Stas as a continuation of medial marginal vein 
Explanation: A i.e. Stas as continuation- of medial marginal vein