Explanation: A VHF "Distress Hot Key" activates a Digital Selective Calling (DSC) distress alert. By regulation and design, this automated digital transmission *always* includes the transmitting station's unique identifier, which is the vessel’s programmed nine-digit Maritime Mobile Service Identity (MMSI) number. It also includes a digital code signaling a distress priority, notifying other DSC radios and Rescue Coordination Centers of an emergency. This ensures rapid, unambiguous identification and prioritization of the emergency call. Other options are incorrect because: A) While crucial, the specific nature of distress is usually added manually *after* the initial hot key activation. Position is included if GPS is connected, but the MMSI and distress priority are the core automated data. B) While a GPS-linked radio will transmit position, course and speed are not always included in the initial automated distress hot key alert. The MMSI is guaranteed. D) The follow-on frequency (typically Channel 16) is understood for voice communications *after* the digital alert, but it's not *included* as data within the initial hot key transmission itself.