Which of following physical abilities is not required as to the routine movement around a vessel?（）

A.Maintain balance and move with agility

B.Climb up and down vertical ladders and stairways

C.Open and close watertight doors

D.Take part in vessel evacuation procedures

针对消费者的销售促进方式有（ ）。

A．样品

B．合作广告津贴

C．折让

D．示范表演