Answer :
The Supreme Court ruling that segregation of White and Black Americans was legal under the separate, but equal principle occurred during **C. after Reconstruction**. This ruling was established in the case of **Plessy v. Ferguson** in 1896.
In the Plessy v. Ferguson case, the Supreme Court upheld the constitutionality of state laws requiring racial segregation in public facilities under the doctrine of "separate but equal." This decision essentially legalized segregation, allowing for separate facilities for White and Black Americans as long as they were deemed to be equal in quality, which, in reality, was not the case.
This era of legalized segregation under the separate but equal principle persisted until it was eventually overturned by the landmark Supreme Court case of **Brown v. Board of Education** in 1954. The Brown v. Board of Education decision declared that state laws establishing separate public schools for Black and White students were unconstitutional, thus marking the end of the era of legalized segregation in the United States.
