What best describes an Alarm signal?

An alarm signal is defined as a critical notification that requires immediate action due to an emergency. When an alarm is triggered, it indicates that potentially dangerous or urgent conditions are present, necessitating a swift response from operators and emergency personnel. This aligns with the primary purpose of an alarm system, which is to alert individuals to situations that could threaten safety or require prompt intervention.

In contrast, the other options outline different types of notifications that do not reflect the urgent nature of an alarm signal. For instance, a scheduled maintenance check is preventive and relates to routine upkeep rather than an immediate response. Similarly, notifications for routine system checks and system alerts for malfunctions indicate issues or maintenance needs that do not require the same level of urgency and rapid action that an alarm does.