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: Surgery
[{'content': 'Commonest cause of pyogenic liver abscess ? \nSelect and explain. \nA. Biliary Sepsis., B. Biliary Colic, C. Appendicitis, D. Sigmoid Diveiculitis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans is 'a' ie biliary sepsis", 'role': 'assistant'}]