Final answer:
The name of the landmark court ruling that mandated the desegregation of American schools is Brown v. Board of Education. This 1954 Supreme Court decision overturned the 'separate but equal' doctrine from Plessy v. Ferguson, declaring segregation in public schools unconstitutional under the Fourteenth Amendment.
Step-by-step explanation:
The landmark court ruling that mandated desegregation of American schools is known as Brown v. Board of Education of Topeka, 347 U.S. 483 (1954). This case challenged the principle of "separate but equal" established by Plessy v. Ferguson and brought to the fore the constitutional violation of racial segregation in public education.
Decided unanimously by the Supreme Court, it was established that segregated schools were inherently unequal, even if they received equal funding, and hence a violation of the equal protection clause of the Fourteenth Amendment. Chief Justice Earl Warren stated in his majority opinion that "separate is inherently unequal," effectively overturning Plessy and removing the legal supports for segregated schools nationwide.
The NAACP played a critical role in this decision, consolidating five separate lawsuits under this case. This ruling was a monumental step in the Civil Rights Movement, marking the beginning of the end for de jure racial segregation in public schools. The correct answer is a) Brown v. Board of Education.