South Carolina was the first state to
D: Implementing literacy tests for voters.
Explanation:
South Carolina has been a historically conservative southern state with a track record of regressive policies in the voting rights and this is shown even in the forward seeming laws of the time which includes the one discussed here.
The state was first of the states that began implementing literacy tests for their voters so as to only make literate people vote which was a thing that happened in southern states more.
It was in 1890 and many people including mostly blacks and native Americans did not know how to read so it effectively ruled them out.