Explanation: In a negative-logic circuit, the convention for assigning voltage levels to logic states is inverted compared to the more common positive-logic system. In standard (positive) logic, a high voltage level typically represents a logic 1, and a low voltage level represents a logic 0. However, in a negative-logic system, these assignments are reversed. Therefore, a low voltage level is used to represent a logic 1, and consistently, a **high voltage level is used to represent a logic 0**. Options B and C refer to "transition levels," which describe changes in voltage over time (e.g., rising or falling edges), not the static voltage levels that define a logic state. Option A, a low level, would represent a logic 1 in a negative-logic system.