What is the main purpose of a fire extinguisher?

The main purpose of a fire extinguisher is to extinguish small fires. Fire extinguishers are designed to be readily accessible and easy to use for individuals to take immediate action on small fires before they escalate. They contain various firefighting agents that target specific classes of fire, allowing for effective suppression of flames in situations where their use is appropriate and safe. This is crucial in minimizing damage, preventing injuries, and potentially saving lives.

Other options serve different roles in fire safety and prevention. A structured escape route is essential for safe evacuation during a fire but does not address fire suppression directly. Alerting authorities is important for managing larger fires but is not the function of a fire extinguisher itself. Containing fire damage is a broader goal of overall fire safety measures and building design, but the extinguisher specifically focuses on fighting the fire at its onset. Thus, option B accurately reflects the primary function of a fire extinguisher.