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
Which of the following is not a Major high risk factor for cholangiocarcinoma: 
Select and explain. 
A. Chronic typhoid, B. Choledocholithiasis, C. C. sinensis infestation, D. Ulcerative colitis
B: Choledocholithiasis
Answer: B: Choledocholithiasis 
Explanation: Choledocholithiasis