【单选题】If a ship,in accordance with the requirements of regulation lO.1.1(of the amendments to the 1974 SOLAS Convention),iffitted with an hunarsat MES, while at sea, shall maintaina continuous watch____.
A.
on at least one of the following HF DSC frequencies: 4207.5kHz, 6312 kHz, 12577 kHz or 16804.5 kHz