Which of the Following Is an Example of De Facto

Which of the following is an example of de facto segregation?

A) in a medium-sized city,the black population living south of the railroad tracks and the white population living north of the tracks
B) creating separate entrances to a restaurant for blacks and for whites
C) separating military units by race into white units and black units
D) restricting the right to vote to those whose ancestors had the right to vote
E) private schools restricting admission to a single race