What is a common signal of dangerous CO levels detected by a CO detector?

A common signal of dangerous carbon monoxide (CO) levels detected by a CO detector is indeed characterized by specific alarm patterns to alert occupants effectively. The correct choice indicates a pattern such as beeping every 4-5 seconds. This type of alert is designed to draw attention without causing panic, giving individuals a clear indication that CO is present in potentially hazardous levels.

The beeping serves as a clear warning system, prompting immediate action, such as evacuating the area and calling for emergency assistance. It ensures that people are aware of the danger and can respond appropriately before the situation becomes critical.

In contrast, other options do not align with standard CO detector alerts. A continuous alarm sound is typically associated with smoke detectors indicating ongoing smoke or fire, while a flashlight alert is not a common feature in CO detectors. Lastly, having no indication at all would not provide any warning of dangerous CO levels, making it ineffective as a safety device. Therefore, the pattern of beeping every 4-5 seconds is the most commonly recognized warning signal for elevated CO concentrations.