Explanation:
The nazis promised to stop the suffering many germans had felt since the end of the world war 1 and make the economy strong again. Unemployment would disappear and Germany would become an autarky though neither of these things truly happened
I'd say the combustion engine, even though it was toyed with in the mid-west during the cowboy era, it wasn't until after the Civil War in which it was a fully effective gasoline powered engine.
The answer is “B: by preserving the nations forest “
