To increase the rate of dissolution of a solute in a solution, the most effective action you could take is to:
Decrease the particle size of the solute because it would increase how often the solute and solvent particles would collide.
When you reduce the particle size, there is a greater surface area for the solvent to interact with the solute, leading to more frequent collisions and quicker dissolution. The other options you've listed would not effectively increase the rate of dissolution.