Final answer:
The main argument of Brown v. Board of Education was that segregation in public schools based on race was unconstitutional, violated the Fourteenth Amendment, and perpetuated racial inferiority, overturning 'separate but equal'. Therefore, the correct option is d.
Step-by-step explanation:
One of the main arguments of Brown v. Board of Education was that segregation of children in public schools solely on the basis of race was unconstitutional. The case brought forward by Linda Brown and her family alongside twenty other African American families argued denial of admission to the elementary school in her neighborhood due to her race. The Supreme Court ruled unanimously that racially segregated public schools violated the Equal Protection Clause of the Fourteenth Amendment, as they perpetuated the harmful idea that African Americans were inferior.
Prior cases had paved the way by securing the right for black plaintiffs to attend public universities, and the NAACP had decided to challenge the broader issue of segregation in public schools by consolidating five lawsuits into the Brown v. The Board of Education case. Ultimately, this landmark decision helped dismantle the 'separate but equal' precedent established by Plessy v. Ferguson and signaled a significant leap forward for civil rights and school integration.