Colligative properties of the solution depend on

Colligative properties are the properties of the solution which does not depend on the nature of the solute. It depends on the ratio of the number of solute particles in the solution to the solvent molecules. This ratio is related to the various units of concentration such as molarity, molality, normality, etc. Colligative properties such as elevation in boiling point, depression in freezing point, osmotic pressure or relative lowering of vapour pressure are found to depend on the number of particles present in the solution. Thus, (c) is the correct option.