What is 17121 in expanded form

If scientists are trying to use what they know about hsv to devise a means of protecting other people from being infected, which of the following would have the best chance of lowering the number of new cases of infection? a) vaccinate of all persons with preexisting cases of hsvb) interfere with new viral replication in preexisting cases of hsvc) treat hsv lesions to shorten the breakoutd) educate people about avoiding sources of infection