Explanation: Enhanced Group Call (EGC) is an Inmarsat satellite service that allows messages to be sent to *selected* groups of ships or to ships within a *defined geographic area*. This capability is crucial for delivering localized information, such as specific storm warnings or a distress alert to a particular vessel, without alerting all ships throughout the vast satellite coverage area. This selective targeting prevents unnecessary alerts to vessels not relevant to the warning or incident. NAVTEX is a terrestrial (MF/HF) broadcast system for navigational and meteorological warnings, not a satellite service. AMVER is a voluntary reporting system used to locate vessels for rescue coordination, not a messaging service. Digital Selective Calling (DSC) is used for direct digital calls between stations or general distress alerts, but EGC provides the specific *area-based* satellite broadcast capability described.