Which of the following was most important in prompting the Americans to support the Immigration Act of 1924?
a. Increased migration of blacks to the North
b. A nativist belief that northern Europeans were culturally superior to the waves of eastern and southern Europeans who had arrived in America over the last forty years
c. A desire to abolish the quota system in the United States
d. A desire to halt immigration from Latin America
e. Fierce economic competition for jobs between northern Europeans, on the one hand, and eastern and southern Europeans, on the other