Hyperconjugation of isopropyl decrease acidity
$\therefore$ order of acidic strength
$(c) > (a) > (d) > (b)$
$\begin{matrix}
O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \,\, \\
||\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
N\equiv C-C{{H}_{2}}-C-C{{H}_{2}}-CH=C{{H}_{2}}\to \\
\end{matrix}$ $\begin{matrix}
OH\,\,\,\,\,\,\,\,\, \\
|\,\,\,\,\,\,\,\,\, \,\,\,\, \\
N\equiv C-C{{H}_{2}}-\underset{H}{\mathop{C}}\,-C{{H}_{2}}-CH=C{{H}_{2}} \\
\end{matrix}$
${C_2}{H_5}OH\,\xrightarrow{{PB{r_2}}}X\,\xrightarrow{{KOH}}\,Y\,\xrightarrow[{(ii)\,{H_2}{O^ + }}]{{(i)\,{H_2}S{O_4}}}Z$
વિધાન $R:$ ઈથેનોલ એ ફિનોલ કરતાં પ્રબળ એસીડ છે.