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': 'The most likely cause of fluctuating jaundice in a middle aged or elderly man is \nSelect and explain. \nA. Peri-ampullary carcinoma, B. Liver fluke, C. Choledochal cyst, D. Carcinoma of pancreas', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]