This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hepatitis Viruses, Subject name: Microbiology
[{'content': 'Hepatitis B vaccination is given to a patient. His serum will reveal: \nSelect and explain. \nA. HBsAg, B. Anti - HBsAg, C. IgM Anti - HBcAg and HBsAg, D. IgM and IgG Anti - HBcAg', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Anti HBsAg (Ref: Ananthanarayan, 9th/e, p. 548 and 8th/e, p. 543)* Anti HBsAg is protective antibody.* It is the only serological marker, present after immunization.", 'role': 'assistant'}]