Explanation: GMDSS Sea Area A-1 is defined internationally as an area within range of at least one VHF coast station where continuous Digital Selective Calling (DSC) alert capabilities are maintained. This ensures that a vessel in distress can initiate an alert via VHF-DSC and receive a timely response. Option B accurately reflects this definition by specifying a coast station equipped with *continuous VHF-DSC capability*. This is the fundamental requirement for a sea area to be classified as A-1, providing automatic distress alerting and acknowledgments. Options A, C, and D are incorrect because they either focus on specific entities (U.S.C.G., Public Correspondence Stations) rather than the critical technical capability, or they omit the crucial "continuous DSC" element. While these stations might exist within an A-1 area, it's the *continuous VHF-DSC watch* that defines the area for GMDSS purposes, not merely being within VHF range of a general communication or correspondence station.