This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
[{'content': 'Epidemiologic study of Hepatitis B is by - \nSelect and explain. \nA. Hbe Ag, B. HBc Ag, C. HBs Ag is used, D. Anti HBc', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Anti HBc appears in serum a week or two after the appearance of HBs Ag. It is earliest antibody marker seem in blood.&remainlifelongg,it is an indicator of prior infection with HBV REF:MICROBIOLOGY ANANTHA NARAYANAN NINTH EDITION PAGE546', 'role': 'assistant'}]