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': 'Investigation of choice in detecting small para-aortic lymph node is - \nSelect and explain. \nA. Ultra sound scan, B. CT scan, C. Lymphangiography, D. Arteriography', 'role': 'user'}, {'content': 'Answer: B \nExplanation: • Investigation of choice in detecting small para-aortic lymph node: CT scan', 'role': 'assistant'}]