Answer
b. Add solute to a saturated solution and heat until all of the solute dissolves. Then, slowly cool to the original temperature.
Step-by-step explanation
A supersaturated solution contains more dissolved solute than required for preparing a saturated solution and can be prepared by heating a saturated solution, adding more solute, and then cooling it gently. Excess dissolved solute crystallizes by seeding supersaturated solution with a few crystals of the solute.
Therefore, a supersaturated solution is prepared by:
b. Add solute to a saturated solution and heat until all of the solute dissolves. Then, slowly cool to the original temperature.