Final answer:
The temperature of the water is the factor that will most affect the rate of dissolving salt into water.
Step-by-step explanation:
The rate of dissolution, or the rate at which a solute such as salt dissolves in a solvent like water, can be influenced by several factors. In this case, the most influential factor among the given options is A) Temperature of the water. Heating up the water increases the kinetic energy of the solvent molecules, resulting in more frequent and energetic collisions with the salt particles, thus increasing the rate of dissolution.
Other factors that can affect the rate of dissolution include B) Stirring the mixture and C) Size of the salt crystals. Stirring the mixture increases the rate of collisions between the solvent and solute, while smaller salt crystals expose more surface area for the solvent to interact with, speeding up the dissolution process.