Correct option is : (A) Vapour pressure
Colligative properties are properties of solutions that depend on the number of solute particles but not on their identity.
The four main colligative properties are:
depression of freezing point, elevation of boiling point, osmotic pressure, and lowering of vapour pressure. However, vapour pressure itself is not a colligative property; it is affected by the number of solute particles, which leads to the lowering of vapour pressure, a colligative property.
