Answer: C) By increasing the surface area of the solute.
Explanation: The rate of reaction means how much time is taken for the reaction to happen. The rate of the reaction depends on the surface area of solute.
When we crush a cube of solute, the surface area increases as more surface of the cube can interact with the solvent and thus the rate of dissolution will increase.
Increasing or decreasing the amount of solvent has no effect on the rate of reaction.