I think it is C) and D). Not sure because I just started this topic. Hope it helps :)
Just one reason? one big reason is they needed jobs. Most immigrants planned to become rich and then go back to their own country. Others immigrated because America was rumored to be perfect.
Jobs would relate most to foreign policy we outsource it so much..
I believe that the answer to the question asked above is that the aftermath of war has carved a lesson and strengthened the trust of its allies. It has built a unique trust which can be gain after the battle.
Hope my answer would be a great help for you. If you have more questions feel free to ask here at Brainly.
