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': 'All are angiographic findings of Thromboangitis obliterans except \nSelect and explain. \nA. Cork screw vessels, B. Rippled ertery, C. Constricted vasa vasorum, D. Spider Leg collaterals', 'role': 'user'}, {'content': 'Answer: C \nExplanation: In TAO(Buerger disease), there is dilatation of vasa vasorum that gives corkscrew appearance to vessels.', 'role': 'assistant'}]