The correct answer is option B. The most dense phase of matter is the solid phase and the least dense are gases. However, there is an exception. Water is the exception. Solid water or ice is less dense than the liquid phase therefore it floats on liquid water.
Density is a measure of how much mass, essentially particles are packed in a unit volume of a substance. So the more packed mass is in a unit volume, the higher the density of a substance. It follows then that a solid, the substance with the most packed arrangement of particles is normally the one with the highest density.
