The stability of tautomers (typically keto-enol forms) is governed by bond energies and stabilizing factors like resonance and hydrogen bonding.

1. General Rule: The Keto form is generally more stable than the Enol form due to the high bond energy of the $C=O$ bond compared to the $C=C$ bond.
2. Exceptions (Enol Stability): The Enol form becomes the major (more stable) tautomer if it is stabilized by:

• Aromaticity: (e.g., Phenol).
• Intramolecular Hydrogen Bonding: In 1,3-dicarbonyl compounds ($\beta$-diketones), the enol form forms a stable 6-membered cyclic ring via intramolecular hydrogen bonding.
• Extended Conjugation: Resonance stabilization between the double bond and the carbonyl group.

Based on the probable answer (III > II > I), Compound III likely possesses the strongest stabilizing factors (such as being an aromatic enol or having strong chelation), followed by II, with I likely being the least stable form (or the destabilized keto/enol form depending on the specific structures).