For a floating vessel,the center of the floating is the point in the waterpiane.（）.

A.aboat which the vessel lists and trims

B.which coincides with the center of buoyancy

C.which, in the absence of external forces, is always vertically aligned with the center of gravity

D.which is shown in the hydrostatic tables as VCB

适度的压力是维持我们正常的心理功能和生理功能的必要条件。