Which substances are classified as natural polymers?
- Aethanol ✓, protein ✓, starch ✓, vinegar ✓
- Bethanol ✓, protein \times, starch ✓, vinegar \times
- Cethanol \times, protein ✓, starch ✓, vinegar \times
- Dethanol \times, protein \times, starch \times, vinegar ✓