Plantation Owners in Early America Often Argued That Enslaved Africans

Plantation owners in early America often argued that enslaved Africans were better off because they did not have the mental capacity to run their own lives. Today, this seems both racist and idiotic. How could such racist beliefs flourish?

A) People are by nature hostile and look to blame their problems on others.
B) Such beliefs justify social arrangements between dominant and minority groups that benefit those who accept them.
C) People knew much less about world history then, so it seemed more plausible.
D) Nineteenth-century science was not well developed, so no authority figures could debunk racist beliefs.