Answer:
A
Step-by-step explanation:
A vaccine is given to an individual to usually prevent us from getting infected by one particular pathogen.
What does a vaccine contain?
The contents of a vaccine contains an antigen known to the virus, which enters the human body, which puts your body on work mode to create antibodies, which is basically like a blueprint to help this foreign invader (the antigen) from never being able to infect the body again.
Therefore, the only correct answer would be A.
B is incorrect because it is the antigen that is exposed, the antibody is the creation due to the antigen being exposed.
C is incorrect because non-specific means that there is no specific antigen that prevents infection, which negates the entire statement.
D is incorrect because a vaccine is specific; that is why we need constant boosters such as for the COVID-19 vaccine to keep up with the new variants and mutations.