Explanation: GMDSS regulations mandate that vessels continuously receive critical Maritime Safety Information (MSI) to ensure safety at sea. NAVTEX is a vital automated system for broadcasting urgent navigational and meteorological warnings and Search and Rescue (SAR) information, especially within coastal areas. Even with an inoperative Inmarsat-C terminal, these essential categories—Meteorological warnings, Search and Rescue information, and Navigational warnings—must remain enabled. These messages provide immediate alerts about severe weather, distress situations, and hazards to navigation, directly impacting the vessel's ability to avoid danger and respond to emergencies. Disabling them would compromise the vessel's safety posture, as they represent the most critical, time-sensitive information a GMDSS Radio Operator needs to receive.