The appropriate reagent for the following transformation is

Which is the most suitable reagent for the following conversion?

The reagents $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ respectively are

$\mathrm{P} \stackrel{{\mathrm{H}}_2/\mathrm{Pd}-{\mathrm{BaSO}}_4}{\to } \mathrm{Q} \underset{\left(\mathrm{ii}\right) \mathrm{dil}. \mathrm{HCl}}{\overset{\left(\mathrm{i}\right) \mathrm{conc}. \mathrm{NaOH}}{\to }} \mathrm{R}+\mathrm{S}$

$\mathrm{R}$ and $\mathrm{S}$ form benzyl benzoate when treated with each other. Hence, $\mathrm{P}$ is

The product $\text{'}\mathrm{P}\text{'}$ is

In set of reactions, identify $\mathrm{D}$

${\mathrm{CH}}_3\mathrm{COOH}\stackrel{{\mathrm{SOCl}}_2}{⟶}\mathrm{A}\underset{\mathrm{Anhydorus} {\mathrm{AlCl}}_3}{\overset{\mathrm{Benzene} }{\to }}\mathrm{B}\stackrel{\mathrm{HCN}}{⟶}\mathrm{C}\stackrel{{\mathrm{H}}_2\mathrm{O}}{⟶}\mathrm{D}$