What best summarizes the central idea of the passage from "Like Mexicans"?

What best summarizes the central idea of the passage from “Like Mexicans”?
a. People from different ethnicities have a difficult time understanding each other.
b. People can be of different ethnicities and still have shared life experiences.
c. People should marry based on shared ethnicity to maintain their own cultures.
d. People should ignore their ethnicities to develop one common culture.