Which of the following is an acceptable audible notification appliance used in a security system?

• A. External loudspeakers
• B. Strobe lights
• C. Self-contained sirens
• D. Silent alarms

Answer: (C)

An audible notification appliance must produce a loud, local alert to warn occupants. A self-contained siren fits this role because it is a standalone unit that includes its own sound-emitting component and power, so it can generate a strong, immediate alarm without depending on external equipment. This makes it a simple, reliable choice for a burglar or residential alarm system.

External loudspeakers can also be audible, but they’re more common for voice evacuation or larger, more complex systems and require integration with a central amplifier. Strobe lights provide a visual alert and don’t make sound, while silent alarms don’t alert occupants audibly at all.