Carboxylic Acids And Its Derivatives

Identify product '\(\mathrm{B}\)' in following reaction.

Cumene \(\xrightarrow[\Delta]{\mathrm{KMnO}_4, \mathrm{KOH}} \mathrm{A} \xrightarrow{\mathrm{H}_3 \mathrm{O}+} \mathrm{B}\)