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
If a patient was immunized with hepatitis B vaccine, which of the following is seen in serum? 
Select and explain. 
A. HBeAg, B. FIBSAg, C. Anti-HBs antibody, D. Anti-HBe antibody
C: Anti-HBs antibody
Answer: C: Anti-HBs antibody 
Explanation: Ans. (c) Anti-HBs antibody