From IMO’S point of view, INMARSAT’s most important function is the provision of（）.

A.general radio communication

B.MSI

C.improved distress and safety communication

D.bridge-to-bridge communication

油断路器的触头接触面有轻微灼伤时，应（）。

A.用细砂布或锉刀打磨修整

B.用干净的布在变压器油中擦洗

C.更换新的触头

D.更换灭弧室