What Was the Supreme Court's Record in Segregation Cases in the Years

What was the Supreme Court's record in segregation cases in the years before Brown v.Board of Education?

A) The Court overturned forms of segregation using the separate but equal rule on factual grounds.
B) The Court had struck down forms of segregation through the commerce clause,not the Fourteenth Amendment.
C) The Court consistently refused to strike down any form of segregation.
D) The Court had already struck down separate but equal as a principle before Brown.
E) The Court had refused to hear cases on segregation before Brown.