3. (3 points) Label each example as either (PI) passive or (AI) active immunity:
a. ________ Bill had chicken pox when he was five. He doesn’t catch it again, even when his nephew gets sick with the virus
b. _______ Billy Jr gets vaccinated with a live attenuated form of the chicken pox virus. He doesn’t get chicken pox after playing with his infected cousin.
c. _______ Bill’s 3 month old daughter is breast feeding. She does not get chicken pox after playing with her infected cousin.