Answer:
C
Explanation:
D in my opinion wouldn't be correct because a vaccine is for if you come in contact with the sickness you are more protected and helps build immunity. So healthy people get them to try and build immunity against said vaccine. Like if you have the flu, your body is fighting. In the Flu vaccine parts of the flu are in the vaccine to help your body learn to become immune. So option C.
Sorry if this is confusing, hope it helps!
