Topside icing decreases vessel stability becauseit increases（）.

A.increases displacement
B.increases the height of the center of gravity
C.increases draft
D.reduces the pocketing of free surface

A.changes in seawater salinity
B.glare on clouds on the horizon
C.changes in air temperature
D.icebergs

A.can usually be detected by radar in a smooth sea at a range of 4 to 6 kilometers
B.are indistinguishable from sea return on the PPI
C.are invisible to radar when covered with a thick layer of snow
D.are usually seen at night before they are close enough to provide a radar echo