Which of the following is a pyrotechnic visual distress signal suitable for both day and night?

The red meteor or red flare is recognized as a pyrotechnic visual distress signal that is suitable for use both during the day and at night. These signals are designed to be highly visible, and their bright red color is easily seen in various conditions. At night, the flare emits a bright light that can be observed from great distances, making it effective for signaling for help. During the daytime, the bright red color stands out against the sky, making it easily noticeable.

In contrast, while other options may be useful in specific situations, they do not meet the same criteria for visibility both day and night. Handheld orange smoke is primarily effective during the day, as its visibility diminishes significantly at night. An electric light, while useful for illumination, does not provide the same immediate and recognizable signal pattern that is associated with distress flares. An orange flag is mostly suited for daytime signaling, lacking the impactful visibility needed at night.