The correct answer is D) All of the above. The basic concept of the Global Maritime Distress and Safety System (GMDSS) is to ensure that shoreside authorities and vessels in the immediate vicinity can be rapidly alerted to a distress situation, allowing for a coordinated search and rescue (SAR) operation with minimum delay. GMDSS achieves this by providing reliable means for ships to transmit distress alerts, receive information about other ships in distress, and communicate with SAR authorities ashore. This comprehensive approach ensures that all necessary parties are informed and can respond effectively to a maritime emergency.