Answer: D . Efforts to change southern racial attitudes and culture ultimately failed because of the South's determined resistance and the North's waning resolve
Step-by-step explanation:
After the Civil War, the North tried to get the South to change their attitudes on race but were unable to. The South seemed to only tolerate blacks as human beings due to the presence of Union soldiers occupying various states in the South.
When the soldiers left, the South reverted back to its racist ways. The North grew more and more tired of trying to enforce equality on the South which meant that the South's attitudes and racial culture continued longer than it should have.