What did the Supreme Court case of plessy v. Ferguson do in the us

A. It upheld sexist laws in the us that prevented women from holding office
B. It granted women the right to vote
C. It upheld racist segregation laws in the us as separation but equal, which became the law of the land
D. It ended the separation but equal legal doctrine

C. It upheld racist segregation laws in the US as "separate but equal," which became the law of the land.