Which of these scenarios would be considered illegal in light of the provisions of the 13th amendment?

a. african american people born in south carolina were forced to tend the fields of a master for no wages.

b. african american people born in north carolina were denied access to polling places to cast their votes.

c. african american citizens were permitted to run for office in the southern states but not the northern states.

d. african american citizens were not permitted to use the same restaurants and educational institutions as white citizens.