A beaker contains a solution of substance 'A' . Precipitation of substance ‘A’ takes place when small amount of 'A' is added to the solution. The solution is -

1. Saturated.

2. Supersaturated.

3. Unsaturated.

4. Concentrated.

Hint: Supersaturated solution.
Explanation:
When solute is added to the solution three cases may arise
(i) It dissolves into solution then solution is unsaturated. 
(ii) It does not dissolve in the solution then solution is known as saturated.
(iii) When solute get precipitated solution is known as supersaturated solution.