Number of ATP molecules used during the preparatory phase of glycolysis:

Explanation

In glycolysis, the preparatory phase involves the conversion of glucose into two 3-carbon molecules known as glyceraldehyde-3-phosphate. This phase requires an investment of 2 ATP molecules to phosphorylate glucose and fructose-6-phosphate. The energy investment is necessary to destabilize the glucose molecule, making it more reactive and primed for subsequent breakdown. Options B, C, and D are incorrect because they do not accurately reflect the number of ATP molecules used in this phase of glycolysis.