Question 2129 Deck Safety

The correct answer is C) natural rolling period. When a vessel inclines, the movement of liquid in a tank causes an increase in the natural rolling period of the vessel. This is because the liquid shifting in the tank changes the vessel's center of gravity, which in turn affects the vessel's metacentric height and ultimately the natural rolling period. The other answer choices are incorrect because they do not directly relate to the effect of liquid movement in a tank on the vessel's characteristics. Righting arm (A), metacentric height (B), and metacentric radius (D) are other stability-related factors, but they are not the primary characteristics affected by the liquid movement in this scenario.