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': "Which of the following test is used to detect perforator incompetence in varicose- \nSelect and explain. \nA. Trendelenberg test, B. Fegan's test, C. Morissey's test, D. Homan's test", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]