Explanation: 406 MHz satellite EPIRBs (Emergency Position Indicating Radio Beacons) are critical maritime safety devices. They are designed to transmit a distress signal to satellites, enabling rapid notification of rescue authorities. Option B accurately describes the key components: * **5-watt 406-MHz alert beacon:** This is the primary high-power transmitter that sends the distress signal to SARSAT satellites. The 5-watt power level is standard for this alerting function. * **Automatic Hydrostatic Release (ARM):** This mechanism allows the EPIRB to automatically float free from a sinking vessel at a certain depth, ensuring it can activate and transmit its signal even if the ship goes down. * **Strobe light:** This provides a visual aid, helping search and rescue teams locate the EPIRB at night or in low-visibility conditions. Options A, C, and D contain inaccuracies regarding the beacon's frequency or power. The 406 MHz beacon typically operates at 5 watts for satellite alerting. The 121.5 MHz beacon, where present, is a lower-power homing beacon (typically 0.25W) for final pinpointing by rescuers, not the primary alerting beacon.