To What Did the Term Solid South Refer in the Decades

To what did the term solid South refer in the decades after Reconstruction?

A) The states of the old Confederacy, which voted Republican in every election for the next seventy years
B) The states of the old Confederacy, which voted Democratic in every election for the next seventy years
C) Four southern states that voted as a bloc over the next decade
D) The states of the old Confederacy, which continued to lobby for the reinstitution of slavery