Mobilization is the answer.
Answer:
Immigration increased child labor,
Explanation: This happened because of the poor immigrant families needing any money they could get, thus sending themselves and their kids off to new jobs.
I'm sure the answers d, because it would help way more than the other options you'd want to know first hand what happen the only way to do so is to speak to those who fought in the war.
I Believe it was president Harry S. Truman