The correct answer is B. Inductance.
When a load is switched off, the current in the circuit tries to continue flowing. This causes a voltage to be induced in the inductor, which can be high enough to cause sparking.
Resistance is the opposition to the flow of current. Inductance is the property of an inductor to store energy in a magnetic field. Capacitance is the property of a capacitor to store energy in an electric field. Impedance is the total opposition to the flow of current in a circuit, and is the vector sum of resistance, inductance, and capacitance.
When a load is switched off, the current in the circuit tries to continue flowing. This causes a voltage to be induced in the inductor, which can be high enough to cause sparking. The higher the inductance, the higher the voltage that will be induced. This is why sparking is more likely to occur in circuits with high inductance, such as motors and transformers.
In addition to inductance, the resistance and capacitance of the circuit can also affect the amount of sparking that occurs. However, the inductance is the most important factor.