What is the purpose of fire extinguishers?

Fire extinguishers are essential safety devices designed specifically to suppress small fires and prevent them from spreading, which is why this choice is the correct one. When a fire occurs, immediate action can be critical in containing it before it escalates into a larger disaster. Fire extinguishers allow individuals to effectively tackle incipient fires, thus minimizing damage and ensuring the safety of occupants.

The other choices, while related to fire safety, do not align with the primary function of fire extinguishers. Creating a barrier against smoke can involve other methods and equipment, such as smoke curtains or ventilation systems, rather than the direct action of using extinguishers. Providing light during an evacuation typically involves emergency lighting or illuminated exit signs, not extinguishers. Similarly, signaling emergencies is usually managed by alarm systems or communication devices, rather than being the role of fire extinguishers, which are intended for fire suppression.