The final product A, formed in the following reaction sequence is
\(Ph-CH=CH_2 \) \(\xrightarrow [\underset{{(iv)\,\text{Mg, ether, then}\,HCHO/H_3O^+}}{{(iii)\,HBr}}]{\overset {(i)\,BH_3}{(ii)\,H_2O_2,\,^{\ominus }OH}}A\)
(1) \(Ph - CH_2 - CH_2 - CH_3\)
(2) \(Ph - \underset{CH_3\,\,\,}{CH\\|}-CH_3\)
(3) \(Ph - \underset {\,\,\,\,CH_2OH}{CH\\|}-CH_3\)
(4) \(Ph - CH_2 - CH_2 - CH _2 -OH\)
