Which device is used for both day and night signaling?

• A. MK-124 Day Night Signal
• B. MK-79 Day Flare
• C. Smoke Signal
• D. Flag

Answer: (A)

This question tests understanding of signaling devices that work in both day and night conditions. The MK-124 Day Night Signal is designed for dual use: during the day it releases bright orange smoke to catch attention, and at night it produces a red flare to be seen in darkness. That combination makes it effective around the clock with a single tool, which is why it’s the best choice when you need a signal usable in any lighting.

The other options are limited to one lighting condition or scenario: the MK-79 is a night signaling flare, useful after dark but not for daytime visibility; a smoke signal relies on daylight to be seen and isn’t effective at night; a flag is visible in daylight and usually requires light or other signaling methods to be seen at night, so it isn’t a true day-and-night signal.