Nazis thought that killing jewish people, roma, and other groups would

a. only make those groups stronger.
b. purify the german race.
c. make germany a safer place.
d. prevent future wars.

They thought this would purify the "The German Race." Since they lost World War 1, they pretty much blamed the Jews. But when hitler came into power he used emotional text and propaganda to make the germans hate jews.

an unexpected salary cut