Why Does Glucose Oxidation Occur in a Series of Steps

Multiple Choice

Why does glucose oxidation occur in a series of steps?

A) One step wouldn't allow the energy released to be harnessed efficiently.
B) It doesn't have to; it just happens to be that way.
C) Glycolysis evolved first and steps were just added over time.
D) Glucose cannot pass into the mitochondria and oxygen cannot enter the cytosol.
E) Glucose is reduced, not oxidized.