The correct answer is D) Both Objected to immigration and believed in the supremacy of white protestants.
The other options of the question were: A) Both groups were originally organized in the south. B) Both supported artists and writers who addressed the cultural changes of the 1920s. C) Both believed that communist has the same rights to freedom of speech as all Americans.
What the nativists and the Ku Klux Klan had in common was that both Objected to immigration and believed in the supremacy of white protestants.
It is correct to say that these two groups opposed immigration because it took jobs that were thought to belong to White Americans and they also did not like the idea that immigrants and minorities' culture could intermingle with the American culture.
However, the Ku Klux Klan took things to the extreme of producing violent riots and persecution of African Americans. They even killed many people.