Examine the diagram of the enzyme catalase below: How does the structure of this enzyme help with its function?

A.
The enzyme's substrate is a mirror image of the enzyme, thus allowing it to reverse any reactions initiated by the enzyme.
B.
The enzyme's shape fits its substrate's shape, thus allowing the enzyme to catalyze the appropriate reaction.
C.
The enzyme is much larger than its substrate, thus allowing the catalyzed chemical reaction to take place inside the enzyme.
D.
The enzyme's active site can change shape in order to match any substrates in need of a catalyst.