The compound is p-methylbenzonitrile, p-CH3​C6​H4​CN, in which the −CN group is attached directly to the aromatic ring.Such aryl nitriles are best prepared by the Sandmeyer reaction.In this route, p-toluidine is first diazotized with NaNO2​ and HCl at 273–278 K to form p-methylbenzenediazonium chloride.The diazonium salt is then treated with CuCN/KCN, which replaces the diazonium group by −CN and gives p-methylbenzonitrile.p-CH3​C6​H4​NH2​NaNO2​/HCl​p-CH3​C6​H4​N2+​Cl−CuCN/KCN​p-CH3​C6​H4​CN+N2​The other routes do not give the required aryl nitrile: p-methylbenzyl chloride with KCN gives p-methylphenylacetonitrile, and aryl halides do not undergo simple nucleophilic substitution with ordinary KCN.Hence the correct option is the one showing diazotization of p-toluidine followed by the Sandmeyer reaction (option c).