What kept the peace in europe until 1914 despite the rapid buildup of armies and weapons

Which of the following is an example of the pull factor known as economic migration? a. better educational opportunities pulling people towards a new country b. mexican laborers entering the us to work in agricultural jobs c. joining family members that are already in a new country d. crop failures driving people away from their country i am unsure on this question, i was thinking b? but i could be wrong.

Who were the sons of liberty? a. colonists who wanted a monopoly on the british tea trade. b. colonial anti-british protestors c. colonists who wanted seats in the british parliament. d. colonists who wanted to block all colonial trade with britain. !

Could anything have been done through compromise to stop it, or did it have to happen?