Every A3 ship, while at sea, shall maintain a continuous watch:
A. On VHF DSC channel 70
B. On the distress and safety DSC frequency 2,187.5 KHz and 8,414.5 KHz and also on at least one of the distress and safety DSC frequencies 4,207.5 KHz, 6,312 KHz, 12,577 KHz or 16,804.5 KHz, appropriate to the time of day and the geographical position of the ship
C. For satellite shore-to-ship distress alerts
D. All of these