Final answer:
c. steady green color. An unacknowledged alarm condition that has returned to normal is most commonly indicated by a steady green color. This is a general practice in industrial control systems, although the actual color used can vary by specific equipment or system.
Step-by-step explanation:
An unacknowledged alarm condition that has returned to normal is typically indicated by a flashing or steady color. The specific colors used can vary depending on the system, but generally, a steady green color is associated with normal operating conditions and no alarm state. Industry standards do not universally dictate the color conventions for alarms, and it will depend on the specific equipment or software vendor's design.
If there is no specific context given regarding the type of equipment or the manufacturer's conventions, the most common interpretation would align with safety and industrial norms where green often represents a safe or 'normal' status. Therefore, based on general practices in industrial control systems, the answer would be (c) steady green color.An unacknowledged alarm condition that has returned to normal is indicated by steady green color.