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
[{'content': 'True about the anatomy of great saphenous vein: \nSelect and explain. \nA. 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', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Stas as continuation- of medial marginal vein', 'role': 'assistant'}]