Assertion: Colloidal solutions show colligative properties.
Reason: Colloidal particles are large in size.
1. Both the assertion and the reason are true and the reason is the correct explanation of the assertion.
2. Both the assertion and the reason are true and the reason is not the correct explanation of the assertion.
3. The assertion is true but the reason is false.
4. The assertion is false but the reason is true.

Hint: Colloidal particles being bigger aggregates, the number of particles in a colloidal solution is comparatively small as compared to a true solution. 
A colligative property is a property of a solution that is dependent on the ratio between the total number of solute particles
(in the solution) to the total number of solvent particles. Colloidal solutions show colligative properties as colloidal particles
have a large size so colloidal particles have a small value of colligative properties because the number of particles is small in
comparison to a normal solution.