Identify the structure of $B$ in the following reaction sequence:
$2,6-\text{dimethylcyclohexane-1,4-dione} + \text{ethane-1,2-diol}$ $\xrightarrow{H^+} A$ $\xrightarrow[2. H_3O^+]{1. LiAlH_4} B$

The product in the given reaction is:

Which one of the following pairs is not correctly matched?

$A$ compound $A$ with molecular formula $C_{10}H_{13}Cl$ gives a white precipitate on adding silver nitrate solution. $A$ on reacting with alcoholic $KOH$ gives compound $B$ as the main product. $B$ on ozonolysis gives $C$ and $D$. $C$ gives Cannizzaro reaction but not aldol condensation. $D$ gives aldol condensation but not Cannizzaro reaction. $A$ is:

What will be the product $B$ in the following sequence of reactions?
$HC \equiv CH$ $\xrightarrow{30\% \, H_2SO_4, \, HgSO_4} A$ $\xrightarrow{NaOH} B$

$A$ reaction of benzonitrile with one equivalent of $CH_{3}MgBr$ followed by hydrolysis produces a yellow liquid $P$. The compound $P$ will give a positive result for which of the following tests?