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
[{'content': 'Cholangiocarcinoma is caused by: \nSelect and explain. \nA. Giardia lamblia, B. Clonorchis infestation, C. Paragonimus infestation, D. Ascaris infestation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b. Clonorchis infestation', 'role': 'assistant'}]