Enzymes are:

Correct option is C

✅ (c) Protein: • Enzymes are biological catalysts, mostly made up of proteins. • They speed up biochemical reactions without being consumed. • Some exceptions are ribozymes (RNA enzymes), but predominantly enzymes are proteins.
❌ (a) Carbohydrate: • Not enzymes, but provide energy or structural function.
❌ (b) Lipid: • Store energy, but not involved in catalytic activity.
❌ (d) None of these: • Incorrect, as enzymes are clearly proteins.