Which of the following is a valid type of distress signal?

A dye marker in the water is a recognized type of distress signal as it is designed to draw attention to the location of a person or vessel in distress. When deployed, dye markers create a visible color in the water, making it easier for rescuers to spot the individual or vessel in need of assistance. This is particularly effective in search and rescue operations, especially in vast open waters, as it enhances visibility.

While a whistle of three blasts, a single loud bang, or a quick wave from a vessel may indicate a need for help, they are not formally recognized as standard distress signals in the same way that a dyed marker is established under internationally recognized safety protocols such as those set forth by the International Maritime Organization. Therefore, the dye marker is the most effective and recognized means of signaling distress in a maritime context.