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': 'In a patient only Anti HBsAg is positive in serum, all other viral markers are negative. This indicates- \nSelect and explain. \nA. Acute hepatitis, B. Chronic active hepatitis, C. Persistent carrier, D. Immunized person with Hepatitis B vaccine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]