Answer:
The correct answer would be heating the mixture.
The solubility of a solute in a particular solvent depends upon the temperature of the solution.
In most cases, the solubility of the mixture increases with increase in temperature of the mixture.
Higher temperature increases the kinetic energy of the solvent due to which it becomes more efficient in breaking apart the particles of the solutes.
It increases the solubility of the solute in a particular solvent.
Thus, more sugar can be added by heating the mixture.
