What did the supreme court determine was unconstitutional in brown v. board of education? integrated schools poll taxes segregation of schools unequal school funding school busing?

The correct answer is

segregation of schools

It ended the policy of separate but equal, declaring that not accepting the African-Americans into Caucasian schools is unconstitutional and that those who wanted to do it were committing something illegal. There was an outrage in the south because of it but they had to accept it.