Final answer:
The Supreme Court's ruling in Brown v. Board of Education outlawed government-imposed segregation in public schools (option b), overturning the Plessy v. Ferguson (option d) 'separate but equal' doctrine and declaring it unconstitutional.
Step-by-step explanation:
The correct statement about Brown v. Board of Education is that it outlawed government-imposed segregation. Specifically, the Supreme Court's decision overturned the Plessy v. Ferguson ruling that had established the 'separate but equal' doctrine, declaring that state laws establishing separate public schools for black and white students were inherently unequal, and therefore unconstitutional. The unanimous verdict of the Court was that the segregation of children in public schools solely on the basis of race was a violation of the Equal Protection clause of the Fourteenth Amendment.
Summing up, Brown v. Board of Education was a landmark case where the Court recognized that the segregation imposed by the public education system was damaging and perpetuated a sense of inferiority among African American children, which contributed to the larger push for civil rights reforms in the United States.