If You Were Vaccinated Against Measles as a Child, You

If you were vaccinated against measles as a child, you still have immunity to the disease decades later because

A) plasma cells secrete cytokines.
B) effector T cells secrete antibodies.
C) vaccinations initiate a secondary immune response.
D) memory B cells can persist in the body for several decades.
E) antigenic determinants from the measles virus remain in your system for decades.