What is the non-pyrotechnic visual distress signal appropriate for use at night?

The non-pyrotechnic visual distress signal appropriate for use at night is an electric light. This type of signal is particularly useful in low visibility conditions, such as nighttime, where traditional flares and pyrotechnics may not be as effective or advisable due to safety concerns and the availability of non-explosive alternatives. Electric lights can provide a constant and visible signal that can be seen from a distance without the risk associated with flares, making them a safe and reliable method for signaling distress after dark.

The other options have limitations that reduce their effectiveness during nighttime. For instance, red flares are considered pyrotechnic products and are not categorized as non-pyrotechnic signals. A white flag is not a distress signal at all, as it's more commonly associated with requests for assistance rather than signaling for help. Orange smoke is also a pyrotechnic signal and is typically effective during daylight hours, not at night, as smoke signals cannot be seen in the dark.