Identify the substrate and product and describe the chemical change in the dehydrogenase-catalyzed reaction involving acetaldehyde and ethanol.

• A. In this hydrogenation reaction, acetaldehyde is the substrate and ethanol is the product.
• B. In this dehydration reaction, acetaldehyde is the substrate and ethanol is the product.
• C. In this reduction reaction, acetaldehyde is the substrate and ethanol is the product.
• D. In this oxidation reaction, acetaldehyde is the substrate and ethanol is the product.

Answer: (C)