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: Microbiology
Cholangiocarcinoma is caused by: 
Select and explain. 
A. Giardia lamblia, B. Clonorchis infestation, C. Paragonimus infestation, D. Ascaris infestation
B: Clonorchis infestation
Answer: B: Clonorchis infestation 
Explanation: Ans. b. Clonorchis infestation