What makes law unconstitutional?

Pls me! the black codes were various state laws in the south concerning african-americans which of the following statements about the black codes is not accurate. a. the black codes protected the civil rights of african-americans. b. african americans who cannot afford to pay a fine could be jailed and then be hired out to anyway person who could pay the fine. c. some southern states passed laws that prohibited is african-americans from voting or serving on jury‘s. d. the black codes were designed to force african-americans into a condition of near slavery.