This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Radiology
[{'content': 'which sign is seen on USG when the femoral vein meets the GSV and femoral aery at saphena femoral junction \nSelect and explain. \nA. Mickey mouse sign, B. String sign, C. Tillaux sign, D. stemers sign', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ref : david sutton 9th ed', 'role': 'assistant'}]