Classify each of the following solutions as saturated, unsaturated, or supersaturated based on the following observations:
(a) Agitation of the solution produces a large amount of solid crystals.
(b) Heating the solution causes excess undissolved solute present to dissolve.
(c) Excess undissolved solute is present at the bottom of the solution container.
(d) The amount of solute dissolved is less than the maximum amount that could dissolve under the conditions at which the solution exists.
