After the WWs, Germany was forced by the rest of the world to pay harsh and heavy reparations. This caused many Germans to be angry and humiliated. It was to these people that fascism's stress on the greatness of the nation appealed to.
Read more on -
Having a fascist ruler with a firm grasp on all aspects of life may have appealed to people who were
anxious to prevent another war
anxious to see order restored after a period of unrest and disorder
unwilling to give up political control to a dictator
angry and humiliated by the harsh treatment Germany received after World War I
Well, let's think about this.
You're a German that just lost the 1st World War due to the Kaiser and now all his pals are running the government. They bent over and let the Allies slap them with some harsh reprimands.
But now here comes a guy saying it wasn't your fault, it was someone else's fault! You're actually a great German in a great nation!
Wouldn't that appeal to you?
The answer is C.