What was the relationship between the Supreme Court decisions in Plessy v. Ferguson and Brown v. Board of Education?

The Supreme Court's decision in Brown overturned the court's decision in Plessy.

The Supreme Court's decision in Plessy affirmed the court's decision in Brown.

The Supreme Court's decision in Plessy overturned the court's decision in Brown.

The Supreme Court's decision in Brown affirmed the court's decision in Plessy.