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
All except one are clinical tests used to test perforator incompetance 
Select and explain. 
A. Pratt's test, B. Trendelenburg- II test, C. Fegan test, D. Morrisey's cough impulse test
D: Morrisey's cough impulse test
Answer: D: Morrisey's cough impulse test 
Explanation: Morrisey's cough impulse test is used for saphenofemoral incompetence.