The factors that encouraged commercial growth in the post classical era include the following: new state practices, new trading organisations and new state sponsored commercial infrastructures. The post classical era refers to the period which immediately followed the ancient history and precede modern history.
The U.S. had been a decisive force in the English and French winning the war and had revealed its vast industrial might. It was well positioned to come out of the shadows and take over the baton of premier world power from Great Britain. It showed the world that when in time America can buckle down and mass produce everything it needed, fast. Ammunition, Tanks, planes, Artillery, all of these were being produced by a unprecedented level and it showed the world that america can beat anyone.
I know the 2nd and the 3rd one are correct.
