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': 'Australia antigen is associated with: \nSelect and explain. \nA. Hepatitis B surface antigen in acute hepatitis, B. AIDS, C. Chronic leukemia, D. Basal cell carcinoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]