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': 'Adson test is used for determining vascular suffiency. It is useful in \nSelect and explain. \nA. Peripheral vascular disease, B. Varicose veins, C. Cervical rib, D. AV fistula', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]