At the state of Equilibrium, the rate of the dissolution of the solute is equal to the rate of the crystallization of the solute i.e. the solute crystal will remain at a constant size.

If the rate of the dissolution is greater than the rate of the crystallization, then the solute crystal in the solution will get smaller.

If the rate of crystallization is greater than the rate of dissolution, then the solute crystal will get larger in the solution.

This equality is the cause of the Equilibrium.

Thus, Option (iii) is the correct answer.