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': 'Which of the following most significantly increases the risk of hepatocellular carcinoma \nSelect and explain. \nA. Hepatitis B virus, B. Hepatitis A virus, C. Cytomegala virus, D. Epstein-Barr virus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans.a. Hepatitis B virus', 'role': 'assistant'}]