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': 'Commonest site of thromboangitis obliterans is \nSelect and explain. \nA. Femoral aery, B. Popiteal aery, C. iliac aery, D. None', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'None' Distal circulation is involved in Buerger's disease, usually distal to popliteal and brachial aery.", 'role': 'assistant'}]