The compound that undergoes decarboxylation most readily under mild condition is

In the following reaction sequence, the compound J is an intermediate.

J(C₉H₈O₂) gives effervescence on treatment with NaHCO₃ and a positive Baeyer's test.

In the following reaction sequence, the compound J is an intermediate.

J(C₉H₈O₂) gives effervescence on treatment with NaHCO₃ and a positive Baeyer's test.

The compound K is

The carboxyl functional group ($$-$$COOH) is present in