The Majority of Immigrants to the United States Prior to 1965

The majority of immigrants to the United States prior to 1965 were from Europe, but since 1965, the majority have been from Latin America and Asia, something that is attributable to the:

A) implementation of affirmative action laws that favored other nations besides Europe
B) surge of refugees seeking asylum following the Vietnam War
C) change in economic status of Latin American and Asian peoples
D) change in preference granted to northern and western Europeans