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: Unknown
[{'content': 'The origin of Klatskin tumors is from \nSelect and explain. \nA. Liver, B. Gall bladder, C. Confluence of cystic duct and hepatic duct, D. Confluence of right and left hepatic ducts', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The tumours arising at the confluence of right and left hepatic ducts at the liver hilus are called Klatskin tumours. These tumours are notable for their slow growing behaviour, marked sclerosing characteristics, and infrequent occurrence of distal metastasis.', 'role': 'assistant'}]