What country did east pakistan eventually become in the 1970's?

What is an example of a secondary source?

List factors that contributed to public confidence in the postwar united states

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.