A valid MMSI number for a DSC call to a specific group of vessels is:

The correct MMSI number for a Digital Selective Calling (DSC) call to a specific group of vessels is based on the allocation of MMSI numbers and the structure defining group calls. When choosing an MMSI for group calling, it is essential that the number begins with a three-digit prefix indicating the region or country, followed by a unique identifier.

For group calls, an MMSI typically starts with "03" for maritime mobile. The number you selected—030327931—fits this requirement perfectly because it communicates the vessel's identification within a specific group, facilitating effective communication.

In contrast, other options may either belong to different categories of MMSI assignments or do not follow the correct structure for group vessel calls based on the requirements of the Global Maritime Distress and Safety System (GMDSS). Thus, they cannot be utilized for this specific purpose. The understanding of MMSI structure is crucial for ensuring proper communication within maritime operations.