Explanation: The GMDSS DSC (Digital Selective Calling) system is engineered for maximum safety and efficiency in distress situations. If an operator fails to manually input specific details when initiating a DSC Distress alert, the control unit will automatically transmit pre-programmed default information. This typically includes the vessel's unique Maritime Mobile Service Identity (MMSI), and if connected to a GPS receiver, the vessel's last known position and time. It will also send an "undesignated distress" category. This crucial design feature ensures that even if an operator is incapacitated or under severe time pressure, a basic, actionable distress message is sent, enabling rescue authorities and other vessels to identify the distressed party and their approximate location. Options A, B, and D are incorrect because they contradict the fundamental safety design of DSC. The system's priority is to transmit *some* form of distress alert. Aborting the transmission (A) or sending no useful information (B, D) would defeat its purpose and endanger lives. Default information is always transmitted to ensure a response.