Which of These Could Reasonably Be Explained by Cultural Subordination

Which of these could reasonably be explained by cultural subordination theory?

A) BEV speakers experience less school success than standard English speakers.
B) Cubans have a higher family income level than African Americans and generally also have a higher rate of school success.
C) Certain groups of Korean students who perform well in U.S. schools tend to perform as poorly, relatively, in Japanese schools as African American students perform in U.S. schools.
D) All of these answers are correct.