Which of the following is listed as a strange thing that can cause false alarms?

• A. Balloons
• B. Fax machines that use heated thermal paper rolls
• C. Insects on sensors
• D. All of the above

Answer: (D)

False alarms often come from unusual, everyday items interacting with detectors in unexpected ways. Balloons drifting around a sensor can move through the detector’s field of view or pop nearby, triggering a motion or acoustic sensor by disturbance. Fax machines that use heated thermal paper can generate heat or electrical noise that some sensitive sensors misread as a trigger, especially in older or highly sensitive setups. Insects on sensors can physically obstruct a lens or interfere with electronics, causing a false reading. Because each of these scenarios can provoke an alarm despite no real threat, all of the above are listed as strange things that can cause false alarms.