The Foreign-Born Population in the United States Reached an All-Time

The foreign-born population in the United States reached an all-time low of 5 percent in 1970 because

A) the Constitution was amended to eliminate naturalization and provide citizenship only to people born within the United States.
B) the federal government chose to deport nearly all foreign-born residents after World War II.
C) the struggling American economy made the United States an unattractive destination for most immigrants.
D) the National Origins quota system placed strong restrictions on the number of immigrants who could enter the United States.