The Enzyme Glyceraldehyde 3-Phosphate Dehydrogenase Catalyzes the Reaction Glyceraldehyde 3-Phosphate $\rightarrow$

The enzyme glyceraldehyde 3-phosphate dehydrogenase catalyzes the reaction glyceraldehyde 3-phosphate $\rightarrow$ 1,3-diphosphoglycerate.The binding of the glyceraldehyde 3-phosphate to the enzyme creates a(n)

A) transition state.
B) activation groove.
C) catalyst.
D) enzyme-substrate complex.
E) energy barrier.