Answer:
b. Plessy vs Ferguson
Step-by-step explanation:
"Plessy v. Ferguson, 163 U.S. 537 (1896), was a landmark decision of the U.S. Supreme Court in which "the Court ruled that racial segregation laws did not violate the U.S. Constitution as long as the facilities for each race were equal in quality, a doctrine that came to be known as "separate but equal"." -Wikipedia