What is the purpose of a booster dose of vaccine? a) to inoculate the body with pathogens b) to increase the levels of serum antibodies c) to eliminate invading pathogens from the system d) to remove the excess serum antibodies in the system

B)to increase the levels of serum antibodies

A person's antibody levels in the bloodstream (called titers) are the body's response to a vaccine. Sometimes when it's been many years since the vaccine, or one's immune system becomes weak, the titers dwindle below efficient numbers. The "booster" is normally a protein from the pathogen which alerts the immune system to reissue it's weapons (the antibodies) against it.