How can inductance be defined?

Inductance can be defined as the property of an electrical circuit that induces a voltage in response to a changing current. This induced voltage acts in opposition to the change in current that created it, according to Lenz's Law, which essentially means that inductance resists changes in current flow. This behavior is a fundamental characteristic of inductors and electromagnetic phenomena in general, where the change in magnetic field due to a current flowing through a coil of wire induces a corresponding voltage.

The other options do not adequately define inductance. An increase in current flow does not describe the property of inductance itself; rather, it refers to a condition that can occur in a circuit. Electrical charge build-up relates more to capacitance than inductance, as it describes how capacitors store charge rather than how inductors store energy in a magnetic field. Lastly, a decrease in resistance under load would indicate a change in the material property of a conductor rather than relating to the inductive properties of a circuit.