the answer would be volume

The boiling point of water is not dependent on mass. The boiling point of water will always be 100°C regardless of the mass or amount of the water. The density of the water will not change since when we divide the mass and the volume of water, we get the constant value called density of water. Any volume of water always has the same density, at a given temperature, making density a characteristic property of water. The electrical conductivity of water will also not change since no matter the mass of water, water will always be able to conduct electricity in the same way. Volume of the water will change since the mass and the volume of the water are directly proportional. When the mass of water changes, the volume of water changes too and vice versa. Hence, the answer is D: Volume.