Which class of fire is involved when smoke is coming from the motor of an exhaust fan?

The correct choice indicates that the fire involves Class C materials, which specifically pertain to electrical fires. When smoke is coming from the motor of an exhaust fan, it is typically an indication that there is an electrical failure or malfunction occurring within the fan's motor. Class C fires involve energized electrical equipment, and in such cases, the recommended method for extinguishing them includes using non-conductive agents, as water would pose a risk of electrical shock.

Class A fires, on the other hand, involve ordinary combustibles like wood or paper, whereas Class B pertains to flammable liquids and gases. Class D involves combustible metals, which would not be relevant in this context. Understanding the classifications of fire is crucial for utilizing the appropriate fire extinguishing technique and ensuring safety when responding to fire emergencies.