Read the section "Vaccines Make People Resistant To Disease." Select the sentence from the section that shows herd immunity has worked to stop diseases. A Its chances to keep spreading can drop to near zero. B Polio was infecting 350,000 people a year in 1988. C Just 33 cases were reported worldwide in 2018. D The protection continues only if people continue to give their bodies a cheat code to beat polio through vaccines.