The position of INMARSAT AOR-W satellite is（）above the equator.

A.one means, whether satellite or terrestrial techniques
B.two means, whether satellite or terrestrial techniques
C.two separate and independent means, each using different radio communication services
D.two means, such as MF DSC and HF DSC

A.satellite /terrestrial system
B.INMAARSAT/COSPAS-SARSAT
C.SART / EPIRB
D.geostationary/polar-orbiting satellites

A.enable SAR operations to start with minimum delay
B.give facilities to marine communication
C.reduce sharply the chances of ship’s sinking
D.both A and C