Answer :
Plessy v Ferguson determined that D) the separate facilities or services for both races be of equal quality.
This is also known as separate-but-equal, which didn't work as well in practice. Segregation then ended with Brown v Board of Education.
The U.S Supreme Court case Plessy V. Ferguson, (1896) determined that segregation was acceptable under the condition that D) The separation facilities or services for both races be of equal quality.