52. Why your immune system responds faster and stronger to the exposure of a pathogen after you have been previously vaccinated against the same pathogen? (A) The vaccine stays in the body permanently to fight the infection. (B) Vaccine-primed memory cells respond quickly to the subsequent pathogen exposure. (C) The vaccine makes the pathogen weaker over time. (D) Your body produces antibodies continuously after vaccination. (E) The pathogen mutates to become less harmful after vaccination.