Isomeric amines with molecular formula $\mathrm{C}_8 \mathrm{H}_{11} \mathrm{~N}$ give the following tests Isomer (P) ⇒ Can be prepared by Gabriel phthalimide synthesis Isomer (Q) ⇒ Reacts with Hinsberg's reagent to give solid insoluble in NaOH Isomer (R) ⇒ Reacts with HONO followed by $\beta$-naphthol in NaOH to give red dye. Isomers (P), (Q) and (R) respectively are