Considering the following reaction sequence, the correct option(s) is(are)

First step of the reaction involves reduction of nitro group to primary amine this can be done using Sn in presence of HCl or H₂/Pd, but aromatic nitro compounds on reaction with ${\mathrm{LiAlH}}_4$produces azo products. 

Second step of the reaction involves diazotization, which involves the use of HNO₂ (or) NaNO₂ in HCl as the reagent ,Para toluene diazonium chloride formed is formed which on hydrolysis produces para-cresol.

And Para toluene diazonium chloride can be converted to benzoic acid by using ${\mathrm{H}}_3{\mathrm{PO}}_2 \mathrm{or} {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$ followed by reaction with ${\mathrm{KMnO}}_4 \mathrm{in} \mathrm{alkaline} \mathrm{medium}$

$\to \mathrm{P}$ may be $\to \frac{{\mathrm{H}}_2}{\mathrm{Pd}}$, ethanol; $\frac{\mathrm{Sn}}{\mathrm{HCl}}$

$\to \mathrm{R}$ may be $\to {\mathrm{NaNO}}_2/\mathrm{HCl};{\mathrm{HNO}}_2$

$\to \mathrm{U}$ may be $\to$ (i) ${\mathrm{H}}_3{\mathrm{PO}}_2$, (ii) ${\mathrm{KMnO}}_4-\mathrm{KOH},\Delta$ or (i) ${\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{OH}$, (ii) ${\mathrm{KMnO}}_4-\mathrm{KOH},\Delta$