Which of the following steps is not used in the fermentation of starch into ethyl alcohol?

• A. Hydrolysis of starch into maltose by diastase present in barley
• B. Conversion of maltose into glucose by maltase present in yeast
• C. Conversion of glucose into ethanol by zymase present in yeast
• D. Conversion of sucrose into glucose and fructose by sucrase present in yeast