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': 'The most common vein to get thrombosed is the ? \nSelect and explain. \nA. Long saphenous, B. Sho saphenous, C. Both, D. Posterior tibial', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is `d' i.e., Posterior tibial", 'role': 'assistant'}]