What are the mandatory DSC watchkeeping bands/channels?

The correct answer highlights the mandatory DSC watchkeeping bands/channels. DSC, or Digital Selective Calling, is an essential feature of the Global Maritime Distress and Safety System (GMDSS) and is used for sending alerts and distress signals. The key channels mandated for DSC watchkeeping include VHF Channel 70, which is specifically designed for DSC calls, and the MF and HF bands, which are also critical for long-range communication, especially in maritime operations.

In this context, the inclusion of 8 MHz HF DSC and 2 MHz MF DSC in the correct choice emphasizes the requirement for vessels to maintain a listening watch on both medium-frequency and high-frequency bands. This ensures that vessels can communicate effectively, especially when they are situated far from shore or in areas where VHF communications might be limited.

The other options do not align correctly with the established guidelines for mandatory DSC watchkeeping channels, either by omitting key channels or by including incorrect frequencies not specified in the GMDSS requirements. Understanding the correct DSC channels is crucial for ensuring effective communication in emergencies at sea and enhances the safety of maritime operations.