What is the Boolean expression for the output of a NOR gate?

The Boolean expression for the output of a NOR gate is correctly represented by stating that the output is the complement of the logical OR operation applied to its inputs. In Boolean algebra, the NOR operation combines the inputs using the OR function and then negates the result. Thus, if K and L are the inputs, the output is true only when both K and L are false, which can be expressed as (F = (K + L)') or equivalently (F = (K + L) \text{ Complementary}). This reflects the fundamental behavior of a NOR gate, making choice C the correct representation of its output.

In contrast, other expressions do not accurately capture the functionality of a NOR gate. For example, combining inputs directly with the AND operation does not reflect the NOR behavior, as it yields an output different from what is produced by a NOR gate.