Read the following passage and answer the following question:

Boiling point or freezing point of liquid would be affected by the dissolved solids in the liquid phase. A soluble solid in solution has the effect of raising its boiling point and depressing its freezing point. The addition of non volatile substances to a solvent decreases the vapour pressure and the added solute particles affect the formation of pure solvent crystals. According to many researches the decrease in freezing point directly correlated to the concentration of solutes dissolved in the solvent. This phenomenon is expressed as freezing point depression and it is useful for several applications such as freeze concentration of liquid food and to find the molar mass of an unknown solute in the solution. Freeze concentration is a high quality liquid food concentration method where water is removed by forming ice crystals. This is done by cooling the liquid food below the freezing point of the solution. The freezing point depression is referred as a colligative property and it is proportional to the molar concentration of the solution, along with vapour pressure lowering, boiling point elevation, and osmotic pressure. These are physical characteristics of solution that depend only on the identity of the solvent and the concentration of the solute. The characters are not depending on the solute's identity.

Identify which of the following is a colligative property?

Osmotic pressure

Following are the colligative properties:

(1) Relative lowering of vapour pressure of the solvent

(2) Depression of freezing point of the solvent

(3) Elevation of boiling point of the solvent 

(4) Osmotic pressure of the solution.