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: Medicine
Klatskin tumour is tumour - 
Select and explain. 
A. At the juncture of cystic duct and bile duct, B. At bile duct, C. At ampulla of vater, D. At the junction of the bile duct
D: At the junction of the bile duct
Answer: D: At the junction of the bile duct 
Explanation: None