Carboxylic Acids And Its Derivatives

Identify product 'B' in the following reaction.

Sodium phenoxide $\xrightarrow[6 \mathrm{~atm}]{\mathrm{CO}_2, 398 \mathrm{~K}} \mathrm{~A} \xrightarrow{\mathrm{H}_3 \mathrm{O}^{+}} \mathrm{B}$