After jacking down your liftboat you have an unexpected list. You find that the only cause of this list must be a flooded leg. The list caused by a flooded leg means your vessel has a(n) __________.

Correct Answer: Option C — decrease in the GZ (righting arm)

A flooded leg on a liftboat adds eccentric weight and reduces effective waterplane area, causing a severe reduction in the righting arm (GZ) curve. This compromises stability according to 46 CFR stability standards for mobile offshore drilling units and self-elevating vessels.