What can an increase in the power of the ku klux klan during the 1920s be attributed to?

a. a rise of nativism and the great migration
b. a rise in nativism and the passage of the nineteenth amendment
c. a rise in immigration of northern and eastern europeans
d. the great migration and the passage of the nineteenth amendment

The Ku Klux Clan is an organization that opposes black people. So having this in mind, the Nineteenth Amendment (which gave women the right to vote) has nothing with them, and neither does the immigration of northern and eastern Europeans. What did attribute to an increase in the power of this organization during the 1920s is A. a rise of nativism and the great migration.
Nativism refers to favoring the status of native people as opposed to immigrants. Great migration refers to the migration of black people from the South to the North of America.