Which of the following would increase the amount to dissolve a solid solute?

By stirring and increasing temperature, there is an increase in dissolving capacity of the solid solute.

Explanation:

If a solute is added to the solution, it doesn't get dissolve easily then we have to increase the temperature, which in turn increases the movement of the solvent (may be water) and the solute particles, thus increases the dissolving power of the solid solute. One more way is by constant stirring, that is by making more contact among the solvent as well as the solute particles there by increasing the solubility of solid solute.

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

i'm assuming that the correct answer is indeed the first one/ "a"..