0pen ullage holes in tanks which are not gas-free must be protected by（）.

A.at its goose neck to such a extent
B.at it's goose neck to such an extent
C.at it's goose neck for such a extent
D.at its goose neck to such an extent

A.assuring heavy cargo is stowed low in the vessel
B.checking the vessel's load line calculations carefully
C.inspection of the hold at completion of discharge
D.stowing the cargo which is to be discharge last on the bottom

A.stored safely at the work site until work is completed
B.returned to the paint locker after each use
C.covered at all times to protect from ignition sources
D.stored in a suitable gear locker