$I.$ ${Sn}-{HCl}$ $II.$ ${Sn}-{NH}_{4} {OH}$ $III.$ ${Fe}-{HCl}$ ${IV} . {Zn}-{HCl}$ $V.$ ${H}_{2}-{Pd}$ $VI.$ ${H}_{2}-$ રેની નિકલ
$PhC{{O}_{2}}H\xrightarrow[2.\,N{{H}_{3}}]{1.\,PC{{l}_{5}}}A\xrightarrow[2.\,{{H}_{2}}/Ni]{1.\,{{P}_{4}}{{O}_{10}}.heat}B.$ અંતિમ નીપજ $(B)$ શું હશે ?