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': 'Bismuth classification for cholangiocarcinoma, type IV is \nSelect and explain. \nA. Common hepatic duct, B. Bifurcation only, C. Bifurcation and B/L secondary intrahepatic ducts, D. Bifurcation and B/L right secondary intrahepatic ducts', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Answer- C. Bifurcation and B/L secondary intrahepatic ducts', 'role': 'assistant'}]