软件维护活动包括以下几类：改正性维护、适应性维护、______维护和预防性维护。

If the hydrostatic release mechanism for an inflatable liferaft is not periodically serviced and becomes inoperative，it will NOT（）.

A.set the water lights on immersion

B.release the dye-marker from the liferaft

C.free the liferaft from the vessel

D.break the seal on the carbon dioxide cylinder