There are many people in the Untied States today whose ancestors (祖先) came from Africa as slaves (奴隶). These people are usually called African Americans (非裔美国人). African Americans prefer (更喜欢)this name rather than "Blacks. " African Amcricans were onee called "Negroes" (黑人)or "colored people." These names are considered (认为) impolile (无礼) today. Black Americans like people to call them ______ A: Negroes B: Blacks C: African Americans