The legal precedent for the 1954 Supreme Court decision in Brown v. Board of Education was

The legal precedent for the 1954 Supreme Court decision in Brown v. Board of Education was
 
  a. the 1943 Supreme Court decision involving Gordon Hirabayashi, in which the plaintiff's lawyer argued that a law was constitutional only if it applied to all citizens, not a specific group.
  b. the 1947 federal court decision in a case brought by the League of United Latin American Citizens against several Orange County school districts where LULAC argued that creating separate schools for Mexican American students violated the Fourteenth Amendment to the Constitution.
  c. the 1941 creation of the Fair Employment Practice Commission to investigate workplace discrimination.
  d. the 1943 repeal of exclusion acts that had targeted Asians, followed by the postwar War Brides Act, which allowed Chinese and Filipino men to bring their wives to the United States.