This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdominal Radiography, Subject name: Radiology
[{'content': 'The cholangiogram shows? \nSelect and explain. \nA. Klatskin Tumor, B. Gall stones, C. Choledocholithiasis, D. Porcelain gall bladder', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Klastskin TumorThe image shows the endoscope in the middle and the biliary tree. You can notice the contrast in gall bladder (9deg clock) and cystic duct where it is meeting the common hepatic duct. However the left and right hepatic ducts are not visible indicating a tumor causing obstruction to flow of contrast.', 'role': 'assistant'}]