In the Context of the Discrimination Against African Americans in Schools,what

In the context of the discrimination against African Americans in schools,what was the Supreme Court's ruling in the Brown v.Board of Education of Topeka,Kansas decision?

A) It ruled that separate but equal doctrine was unconstitutional.
B) It ruled that split labor markets were illegal,and people involved in this type of trade would be punished.
C) It ruled that minority groups should assimilate into the mainstream.
D) It ruled that all forms of institutionalized discrimination should be nullified.