${C_6}{H_5}C{H_2}CH(OH)CH{(C{H_3})_2}\xrightarrow{{conc.\,{H_2}S{O_4}}}\,?$
$\left. \begin{gathered}
(A)\,\,\xrightarrow{{PB{r_3}}}\,(C)\,\xrightarrow{{Mg\,,\,ether}}Grignard\,\,reagent \hfill \\
(A)\,\,\xrightarrow[{{H_2}S{O_4}}]{{N{a_2}C{r_2}{O_7}}}\,(B) \hfill \\
\end{gathered} \right\}$ $ \to \,(D)\xrightarrow{{{H_3}{O^ \oplus }}}$ $(3,4-$ ડાયમિથાઇલ $3-$ હેકઝાનોલ l$)$