Answer:
I would say poor economic conditions after World War One. Choice B.
Step-by-step explanation:
The German people were basically dirt poor from all the sanctions and restrictions placed on them by the "Treaty of Versailles". This led to many of the German people resenting people of other nations and fueled the nationalist sentiment that led to the rise of the Nazi party who promised to bring Germany back into greatness.
If you have time, definitely check out some articles and papers about the "Treaty of Versailles" and you'll quickly understand the hardship of the German people pre World war II.
Cheers.