X and Y are the reactants in a chemical reaction catalysed by the enzyme E. Z is the product. The first three steps of the reaction are shown. $X + E \rightarrow XE$ $Y + XE \rightarrow XYE$ $XYE \rightarrow ZE$ What is the fourth, final step in this reaction?
- A$X + Y + E \rightarrow Z$
- B$X + YE \rightarrow Z$
- C$Y + ZE \rightarrow YZ + E$
- D$ZE \rightarrow Z + E$