The correct answer is: C. between 0 and 1.
The relative density of sand is a measure of how closely packed the sand particles are. It is defined as the ratio of the dry density of the sand to the density of the solid grains of the sand. The relative density of sand can range from 0 to 1, where 0 represents the loosest state of sand and 1 represents the densest state of sand.
When sand is in its densest state, the sand particles are packed as closely together as possible. This means that there is very little air space between the particles. The relative density of sand in its densest state is typically between 0.6 and 0.9.
When sand is in its loosest state, the sand particles are not packed as closely together. This means that there is more air space between the particles. The relative density of sand in its loosest state is typically between 0.3 and 0.6.
The relative density of sand is an important factor in determining the engineering properties of sand. For example, the relative density of sand affects the strength, compressibility, and permeability of sand.