In the given reaction, identify compound $[\mathrm{A}]$
(a) Compound $[\mathrm{A}]$ is
(b) Compound $\mathrm{A}$ is $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}$ $\mathrm{Br}$
(c) Reagent $\mathrm{B}$ is $\mathrm{H}_{2} / \mathrm{Ni}$ at $120^{\circ} \mathrm{C}$
(d) Reagent $B$ is LiAlH $_{4}$