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: Pathology
[{'content': "Which of the following is called as Klatskin's tumor \nSelect and explain. \nA. Fibrolamellar hepatocelluar carcinoma, B. Hilar cholangiocarcinoma, C. Gall bladder adenocarcinoma, D. Intrahepatic cholangiocarcinoma", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Perihilar cholangiocarcinoma is also called Klatskin tumors. They occur at the bifurcation of right and left hepatic ducts.', 'role': 'assistant'}]