What labeling indicates a Class C fire extinguisher?

A Class C fire extinguisher is indicated by a blue circle. This classification is specifically designed for fires involving energized electrical equipment. The blue color of the circle serves as a visual cue, helping emergency responders and individuals to quickly identify the appropriate extinguisher for such scenarios.

Other options represent different classes of fire extinguishers; for instance, the red square typically corresponds to Class A extinguishers for ordinary combustibles, like wood and paper. The green triangle is used for Class B extinguishers, which are suitable for flammable liquids and gasses. The yellow star does not have a standard designation in the context of fire extinguishers. Understanding these labels assists in ensuring that the right type of extinguisher is readily available, promoting safety during fire emergencies.