To determine whether the density of the Custom Cube or the water is greater, you need to assess the floating condition. When an object floats stationary in water, the densities of the object and the water are related as follows:
- If the object's density is greater than the water's density, it will sink.
- If the object's density is less than the water's density, it will float.
- If the densities are equal, the object will remain suspended in the water.
Since the problem states that the Cube is floating stationary in the middle of the water, the density of the Cube must be less than or equal to the density of the water.
Therefore, the best answer is:
The density of the water.