Haloalkanes And Haloarenes

The reactions taking place with \(\mathrm{2- Phenyl-2-bromopropane}\) as the starting material is shown below. Identify [A] and [B] formed in the reaction.

\(\mathrm{C}_6 \mathrm{H}_5-\mathrm{C}\left(\mathrm{CH}_3\right)_2^{-} \mathrm{Br} \xrightarrow[\Delta]{\text { KOH Alcoholic }}[\mathrm{A}]\)

\([\mathrm{A}]+\mathrm{HBr} \xrightarrow{\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{CO})_2 \mathrm{O}\right.}[\mathrm{B}]\)