Which situation is the best example of opportunity cost?

After world war 1 immigration was based on

What is one way the spanish war of independence encouraged those in the colonies to seek new political and economic rights? colonies took advantage of spain’s weakened ability to prevent rebellion. the disruptions caused by the war encouraged colonial merchants to seek markets in the pacific. the exposure to french ideas through the war convinced many in spain to provide these liberties to the colonies. the war with france made spain tighten their political and economic hold on the colonies in desperation.

Between 1870 and 1916, approximately how many immigrants came to the united states? 10 million 25 million 75 million 125 million