Which of the following must a 16-foot canoe have on hand when away from the dock after dark?

A 16-foot canoe must carry at least a flashlight or lantern when away from the dock after dark to ensure safety and visibility. Lighting is essential for navigating and signaling in low-light conditions, helping to prevent collisions and ensuring that the canoe is visible to other boaters. Proper lighting devices are critical for maintaining safety on the water, as they help the operator see potential hazards and allow others to see the canoe.

In some situations, other options such as a red flare or a signal mirror may be useful, but they do not replace the necessity of having a reliable and continuous light source like a flashlight or lantern. A portable radio, while a valuable tool for communication, does not address the immediate need for visibility and navigation at night, which is the primary concern when operating a canoe after dark.