The correct answer is: C. more negative voltage.
In negative logic, a logic state 1 corresponds to a more negative voltage than a logic state 0. This is in contrast to positive logic, in which a logic state 1 corresponds to a more positive voltage than a logic state 0.
Option A is incorrect because a logic state 1 in negative logic does not correspond to a negative voltage. Option B is incorrect because a logic state 1 in negative logic does not correspond to zero voltage. Option D is incorrect because a logic state 1 in negative logic does not correspond to a lower voltage level. Option E is incorrect because the answer is C.