Which of the following best explains why most immigrants came to the United States between 1865 and 1920?

A. Most immigrants were wealthy Europeans who brought successful businesses to the United States.
B. Most immigrants faced problems at home. They believed that there was much more opportunity for them in the United States than at home.
C. Most immigrants came to the Oregon Territory, where married couples were given 640 acres of land for free.
D. Most immigrants did not expect to find much opportunity in the United States. But many were expelled from their homelands.