Fluid Mechanics

The buoyant force on an object is given by the equation , where is the density of the fluid, is the volume of the displaced fluid, and is the acceleration due to gravity. The buoyant force depends directly on the density of the fluid in which the object is submerged. Since seawater has a higher density than fresh water, the buoyant force experienced by an object will be greater in seawater because it displaces more mass per unit volume. This leads to a stronger upward force on the object when submerged in seawater.

Therefore, the correct answer is (c) seawater has greater density.