Final answer:
Diluting with water would slow down the reaction rate.
Step-by-step explanation:
The enzyme maltase catalyzes the hydrolysis of maltose into glucose molecules. Several factors can affect the rate of this reaction, but in the given options, diluting with water would slow down the reaction rate. This is because diluting the maltose solution with water decreases the concentration of maltose, which in turn decreases the rate of enzymatic hydrolysis.