Which of the following actions is a first step in responding to a fire emergency?

Activating the fire alarm is crucial as a first step in responding to a fire emergency because it alerts all occupants of the danger, ensuring that everyone is made aware of the situation. This action initiates the emergency response procedures and signals to trained personnel and emergency services that intervention is needed. It helps in mobilizing resources and ensures that everyone can begin evacuation or other necessary measures in a coordinated manner.

While attempting to extinguish the fire, evacuating the area, or calling for help are important actions, they should typically follow the activation of the fire alarm. Activating the alarm establishes a formal alert system which is vital for ensuring safety and efficiency during a fire emergency. This step prioritizes collective safety and communication, which are essential elements in managing any potential fire incident effectively.