The correct answer is B.
The treaty of Versailles imposed on Germany a very heavy burden in terms of reparation payments. The amount set to be paid was totally impossible to reach and the German economy was severly limited by its huge debt. Extreme problems arised as the hyperinflation of the German currency (1918-1924), that took place between the two world wars, during the Weimar Republic.
This situation brought an intense political intestability. Inside this very tense atmosphere, the Nazi party started preaching its ideas related to German pride and superiority, German people first, spreading its racists ideas against foreigners who were stealing the wealth which should pertain to the Germans (Jews, the Allies), etc. And these speeches that arrived at the same time of the economic suffering that was affecting the German population, together with the excellent abilities of the Nazi leaders in terms of oratory, started to gather popular support for the Nazi party and political ideas.
When the Nazis managed to win the elections and to control the country's politics, they started their invasions in other European territories, including the demilitarized zone.