Which of the Following Was an Indication of the Prevalence

Which of the following was an indication of the prevalence of racial thinking in the United States during World War II?

A) All legislators of German descent were forced to resign.
B) German, Italian, and Japanese language classes were banned at every university.
C) Citizens of Japanese descent were forced to give up their homes and businesses and relocate to internment camps.
D) All citizens of German descent had to take an oath of loyalty to the United States, even if they were American-born citizens.