What specifically was Dr. Martin Luther King Jr. speaking out against when he made this statement in 1958?

“I could never adjust to the separate waiting rooms, separate eating places, separate rest rooms, partly because the separate was always unequal, and partly because the very idea of separation did something to my sense of dignity and self-respect.”

A.
civil disobedience
B.
the Montgomery Bus Boycott
C.
the march on Selma, Alabama
D.
Jim Crow laws
E.
integration of public schools