Which false scientific theory did the nazis use to justify their persecution of jews? a. phrenology b. mysticism c. racism d. astrology

The Nazis used the racism as a "theory" (but is a false theory) to justify their persecution of Jews. 
The racism centered around the concept of race. The Nazis wanted a "pure" race, aryans, and they had to exterminate the Jews.

Racism is the answer given, but it's not a scientific theory, if you want the bald faced truth, evolution is the scientific theory that Hitler used to elevate the Aryan race above all other 'races' and justify the extinction of less 'evolved' homo sapiens.