The Activity of an Enzyme Was Examined in the Laboratory

The activity of an enzyme was examined in the laboratory as it catalyzed the formation of a product molecule, B, from a substrate, A.This reaction was carried out in an aqueous solution consisting of water and copper sulfate at a pH of 7.While attempting to repeat the experiment, a biochemist uses a solution of pure distilled water (pH = 7) and observes that the rate of formation of B has decreased dramatically.Which is a possible explanation for this result?

A) The enzyme's optimal activity is not at pH 7.
B) The enzyme needs the presence of a buffer to function.
C) B is unstable and cannot be measured.
D) The enzyme needs copper ions to act as cofactors for optimal enzyme activity.
E) Sulfate ions inhibit binding of A to the enzyme's active site.