A →[ (ii) CN^- (iii) H_2 O / H^+ ] (i) Cl_2, Δ 4-Bromophenyl acetic acid. In the above reaction ' A ' is

$\displaystyle \mathrm{A} \xrightarrow[\substack{\text { (ii) } \mathrm{CN}^{-} \\ \text { (iii) } \mathrm{H}_2 \mathrm{O} / \mathrm{H}^{+}}]{\text { (i) } \mathrm{Cl}_2, \Delta}$ $\displaystyle 4$-Bromophenyl acetic acid. In the above reaction ' A ' is