Explanation: GMDSS satellite EPIRBs are crucial safety devices designed for global distress alerting. * **Float-free release bracket:** This feature, often incorporating a hydrostatic release mechanism, allows the EPIRB to automatically deploy and float to the surface if the vessel sinks, ensuring it can activate even if no one is able to manually deploy it. * **Strobe light:** Once activated, a high-intensity strobe light flashes to provide a visual aid for rescue forces, particularly useful in low light or darkness. * **Distress alert transmission on 406 MHz:** This is the primary function of a GMDSS EPIRB. It transmits a coded distress signal via satellite (COSPAS-SARSAT system) to a Rescue Coordination Center, identifying the vessel and its location. This is the core of its global alerting capability. Let's look at why other options are incorrect: * **A) Distress homing transmission on 406 MHz:** 406 MHz is for satellite *alerting*, not local homing. Homing is typically on 121.5 MHz or via AIS. * **B) AIS homing frequency:** While some modern EPIRBs integrate AIS for local homing, it's not a universal primary homing frequency for the EPIRB itself in the same way 121.5 MHz was, and the option omits the essential strobe light. * **D) Distress alert transmission on 121.5 MHz:** 121.5 MHz is used for *local homing* by aircraft and vessels, not for satellite distress *alerting*. The primary satellite distress alert frequency for GMDSS EPIRBs is 406 MHz.