Which of the following is an example of a fire alarm initiating device?

A manual pull station is an example of a fire alarm initiating device because it is designed specifically to alert the fire alarm system when a fire is detected or suspected. When someone pulls the handle of the station, it sends a signal to the fire alarm control panel, which then activates the alarm system, notifying occupants of the building to evacuate and potentially alerting emergency services. This direct action to initiate a response makes it a critical component of fire safety systems.

In contrast, the other options do not serve as initiating devices. An emergency exit sign provides information about exits to ensure a safe evacuation route, but it does not directly alert the fire alarm system. A fire extinguisher is a tool used to combat small fires but does not initiate an alarm. Likewise, a smoke vent helps to control smoke during a fire but does not send a signal to the fire alarm system. Thus, a manual pull station stands out as an essential initiating device in fire alarm systems.