Explanation: The Global Maritime Distress and Safety System (GMDSS) fundamentally enhances maritime safety by ensuring that distress alerts are received quickly and reliably. Its core concept, as described in option C, is twofold: to directly alert Search and Rescue (SAR) authorities ashore to a distress situation and simultaneously inform other shipping in the vicinity, allowing them to provide immediate assistance. This is achieved through integrated technologies like Digital Selective Calling (DSC), EPIRBs, and satellite communications. Option A is incorrect because GMDSS is designed to provide direct, automated alerts to shoreside authorities, rather than relying solely on indirect reports from other vessels. Option B is incorrect as GMDSS aims to streamline and accelerate the distress alerting process, minimizing bureaucratic chains to facilitate a rapid response. Option D is also incorrect; while confirmation may occur, SAR authorities are designed to act on initial EPIRB alerts promptly, not to delay action waiting for follow-up confirmation, which would compromise response time.