In keto - enol tautomerism of dicarbonyl compounds, the enol form is preferred in contrast to the keto-form this is due to
Presence of carbonyl group on each side of -CH2-group
Resonance stabilisation of enol form
Presence of methylene group
Rapid chemical exchange
Resonance stabilization of enolform as shown below
In which one of the following keto-enol system is the keto form more stable than the enol form?
Keto-enol tautomerism is observed in