An example of an oxidation–reduction enzyme is

Correct answer: dehydrogenase.

Explanation: Oxidation–reduction (redox) enzymes are typically oxidoreductases, which transfer electrons or hydrogen between molecules. Dehydrogenases catalyze the removal (or addition) of hydrogen (often using NAD⁺/NADH or FAD/FADH₂), so they are classic redox enzymes.

• Amylase – a hydrolase that breaks starch into sugars (no redox).
• Protease – a hydrolase that breaks peptide bonds (no redox).
• Lipase – a hydrolase that breaks fats into glycerol and fatty acids (no redox).
• Dehydrogenase – oxidoreductase (redox enzyme) transferring H/e⁻.