Which of the following best describes the role of a buoy?

The role of a buoy is best described as an anchored float used for marking underwater hazards. Buoys are essential navigational aids in both marine and inland waterway environments. They serve various purposes, such as marking the boundaries of safe navigation channels, indicating the presence of underwater obstacles, alerting mariners to shallow areas, and guiding boats safely through tricky waters.

By being anchored in place, buoys provide a reliable point of reference for vessels, allowing mariners to navigate safely while avoiding potential hazards. Their visibility and placement are critical for maritime safety, ensuring that they can be seen from a distance during both day and night, sometimes enhanced by light or sound signals.

Other options do not capture the primary purpose of a buoy. While a dock is a facility for mooring vessels, it lacks the navigational function of a buoy. A signal for rescuers is more related to emergency signals rather than the consistent navigational role a buoy plays. Similarly, while some buoys can serve navigational purposes, they are not classified as a type of navigational instrument like a compass or GPS. Therefore, option B provides the most accurate and comprehensive description of a buoy’s function.