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
[{'content': 'Cancer caused by chronic parasitic infection - \nSelect and explain. \nA. Cholangiocarcinoma, B. Hepatic cell Ca, C. Ca GB, D. Ca pancreas', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]