What is the product $P$ obtained in the following reaction? $CH_3CH_2Br + AgCN_{(alc)} \rightarrow P$

$R-X + NaNO_2 \to P + NaX$
$R-X + AgNO_2 \to Q + AgX$
$P$ and $Q$ are related as

Two isomers $(A)$ and $(B)$ with molar mass $184 \ g/mol$ and elemental composition $C, 52.2 \ \%; H, 4.9 \ \%$ and $Br, 42.9 \ \%$ give benzoic acid and $p$-bromobenzoic acid,respectively,on oxidation with $KMnO_4$. Isomer '$A$' is optically active and gives a pale yellow precipitate when warmed with alcoholic $AgNO_3$. Isomer '$A$' and '$B$' are,respectively .... .

Among the following,which will readily undergo $S_{N}2$ reaction?

Which of the following statements is incorrect regarding benzyl chloride?

Given below are two statements:
Statement $I$: $(CH_3)_3C-CH_2-Cl$ will undergo $S_N1$ reaction even though it is a primary halide.
Statement $II$: It will not undergo $S_N2$ reaction very easily even though it is a primary halide.
In the light of the above statements, choose the most appropriate answer from the options given below: