Which type of light is always on?

The correct answer is a fixed light, which is characterized by a constant and uninterrupted beam of light that is always on. This type of light is often used in navigational aids, such as lighthouses or buoys, to provide a reliable point of reference for mariners. Fixed lights are crucial in helping vessels determine their position relative to hazards or safe passage areas, especially in poor visibility conditions or during nighttime.

In contrast, minor lights can be intermittent or low-intensity lights used for specific locations, while flashing lights and occulting lights operate based on patterns or sequences (flashes occurring at intervals or periods of light and dark). This variability makes them less predictable when compared to fixed lights. Therefore, the constant illumination of a fixed light makes it the most reliable type among the options provided for navigation purposes.