The PH of the Solution in Which an Enzyme-Controlled Reaction

The pH of the solution in which an enzyme-controlled reaction takes place

A) is not important, since enzymes work well at a variety of pH levels.
B) is important, because changing the pH changes the shape of the enzyme.
C) is important, because changing the pH increases the temperature and the enzyme is denatured.
D) alters the substrate and, therefore, prevents the enzyme from attaching to the substrate.