Which type of signaling device is NOT approved for long-term use?

The correct choice indicates that green lasers are not approved for long-term use as a signaling device in maritime situations. While green lasers can be effective in certain circumstances for visual signaling to aircraft or vessels, they are not officially recognized or endorsed for long-term maritime distress signaling as the other options are. Their primary purpose is more aligned with short-term signaling rather than sustained emergencies, which makes them unsuitable for long-term use.

Red parachute flares, orange smoke signals, and red hand flares are all considered reliable and effective signaling devices for emergencies in maritime contexts. These devices are designed to provide clear and long-lasting signals that can attract attention over extended periods, which is essential during rescue operations or when signaling for help in distress situations. Their approval derives from their proven effectiveness and safety in maritime emergency signaling.