The organometallic compound $\left(\mathrm{CH}_3\right)_3 \mathrm{CMgBr}$ on reaction with $\mathrm{D}_2 \mathrm{O}$ produces $\qquad$

In the following scheme of reaction.

X, y and Z respectively are

A haloalkane undergoes $\mathrm{S}_{\mathrm{N}} 2$ or $\mathrm{S}_{\mathrm{N}} 1$ reaction depending on

Identify A, B and C in the sequence.

$$\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Br} \underset{\text { Alc. }}{\stackrel{\mathrm{KCN}}{\longrightarrow}} A \stackrel{\mathrm{LiAlH}_4}{\longrightarrow} B \stackrel{\mathrm{HNO}_2}{\longrightarrow} C$$