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
In a patient only HBs Ag is positive ins serum, all other markers are negative, This indicates - 
Select and explain. 
A. Acute hepatitis, B. Chronic active hepatitis, C. Persistent carrier, D. Hepatitis B vaccination
D: Hepatitis B vaccination
Answer: D: Hepatitis B vaccination 
Explanation: Presence of only HBsAg indicate immunisation. REF:MICROBIOLOGY ANANTHA NARAYANAN NINTH EDITION PAGE.546&548