According to the Supreme Court ruling in the Plessy v. Ferguson case, why was segregation acceptable?

A Segregation was legal because African-Americans were not citizens
B Segregation was legal as long as the facilities for black and whites were equal
C Segregation was acceptable in private business is only
D Segregation was acceptable on a state-by-state basis

B Segregation was legal as long as the facilities for black and whites were equal