Which of the following frequencies and modes is allocated for Distress alerting in GMDSS?

Correct Answer: Option D — All of the above

GMDSS mandates multiple layers of distress alerting. These include 406 MHz satellite EPIRBs, Inmarsat satellite systems (1626.5-1645.5 MHz), VHF Channel 70 DSC, and six dedicated MF/HF DSC frequencies. All listed systems serve as core components of the Global Maritime Distress and Safety System.