Answer: D.
It means that they are against "pluralism".
Step-by-step explanation:
Pluralism involves recognizing and accepting people with different views, cultural backgrounds and opinions from the main culture of a larger society. In such a pluralist society, people coexist and live together in peace.
The United States is an example of a pluralist society.
In this case, the conservative groups campaigning to reduce the number of people coming into the United States are against pluralism.