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 except one are clinical tests used to test perforator incompetance \nSelect and explain. \nA. Pratt's test, B. Trendelenburg- II test, C. Fegan test, D. Morrisey's cough impulse test", 'role': 'user'}, {'content': "Answer: D \nExplanation: Morrisey's cough impulse test is used for saphenofemoral incompetence.", 'role': 'assistant'}]