Question

what was the "melting pot" theory?

A. immigrants from all over leaving America in search of better lives back home
B. immigrants to the United states coming together to create American culture
C. American citizens persecuting new immigrants
D. American Indians protesting the influx of immigrants

Answer 1

B is your answer, as the melting pot is a conglomeration of many cultures from around the world. 

Answer 2

B, "immigrants to the United States coming together to create American culture".

The whole idea of the "melting pot theory" was the combining of culture and backgrounds to ideally become one culture.