The purpose of the GMDSS is to（）safety of life and property at sea all over the world.

A.taking the place of the radio system
B.introducing a new life-saving system
C.saving the vessels in distress
D.improving the communication on land

A.was suffering
B.is suffering
C.has suffered
D.has been suffering

A.see
B.seeing
C.be seen
D.being seen