It's mainly because of A and B, because after the war, the industrial resolution happened, and farmers are replaced by machines, farmers has no work to do, their speed is no compare to the machines, so they must move to another place. Also the population in Europe is growing in a extremely fast speed. Hope that helps :)
Answer:
Chandragupta Maurya
Chandragupta Maurya (c. 321 - c. 297 BCE), known as Sandrakottos (or Sandrokottos) to the Greeks, was the founder of the Maurya Dynasty (4th-2nd century BCE) and is credited with the setting up of the first (nearly) pan-Indian empire
Explanation:
The louisiana purchase in 1803 doubled the size of america
it would be B,
search for letter written by poor laborers during the Great Depression
