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': 'In cholangiography CBD stone appears as ? \nSelect and explain. \nA. Meniscus sign, B. Cut off sign, C. Slight flow of dye from the sides of stone, D. Chain of lake appearance.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans is a ie Meniscus sign', 'role': 'assistant'}]