Social Darwinism is a racist belief that A.Imperialism benefits weaker races
B.Africans should be slaves
C.Charles Darwin was a racist
D.Imperialism is evil

CAN SOMEONE HELP ME PLS

The answer is A.

Explanation:

Social Darwinism is a theory which applies evolutionary theories to countries, not accounting for the idea that countries don't well... reproduce. It implies that if a country, such as Britain, is able to take control of another, such as Antigua, that country must be superior. For an example of British imperialism in Antigua, you can read Jamaica Kincaid's account in her  essay "On Seeing England" where she recounts her early education in a British Antigua. It generally states that the defeated country is helped by being absorbed by the decidedly superior one (a racist belief implying that imperialist white nations are superior to ethnic, native, and black nations and groups who were peaceful before being conquered).

Hope this helps.

A. Is probably the correct answer.

If you look at the names, they work as a giveaway. 
Rulers are made, well, to rule
Freemen sound like they aren't dependent on anyone
Dependents sound like they depend on people for social status
Slaves don't have any social rights.