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
[{'content': 'Lower leg perforator is between \nSelect and explain. \nA. Femoral vein and great saphenous vein, B. Posterior tibial vein and saphenous veiin, C. Posterior tibial vein and posterior arch vein, D. Peroneal vein and short saphenous vein', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Lower leg perforator is between posterior tibial vein and posterior arch vein (a tributary of GSV).', 'role': 'assistant'}]