In the given conversion,the best yield will be obtained with:

Identify the principal product of the following reaction:

The product of the reaction is

Product $(B)$ is :

Considering the following reaction sequence,the correct statement$(s)$ is(are):
$A$. Compounds $P$ and $Q$ are carboxylic acids.
$B$. Compound $S$ decolorizes bromine water.
$C$. Compounds $P$ and $S$ react with hydroxylamine to give the corresponding oximes.
$D$. Compound $R$ reacts with dialkylcadmium to give the corresponding tertiary alcohol.

Statement $I$: Aldehyde on reaction with $HCN$ gives Cyanohydrin.
Statement $II$: Cyanohydrin is a compound which consists of hydroxy and cyano groups on the same carbon.
Choose the correct answer from the following with reference to above statements.