Which of the following reactions uses $SnCl_2/HCl$ as a catalyst?

The reaction is given as follows:
$Ph-CO-N(CH_3)(OCH_3) + 2CH_3MgBr \xrightarrow{H_3O^+} (P)$
Product $(P)$ is:

The product $(B)$ of the following reaction is:

Consider the following reactions:
$C_2H_2 + H_2O \xrightarrow[333 \ K]{Hg^{2+} / H^{+}} [X] \stackrel{\text{Isomerisation}}{\rightleftharpoons} Y$
$Y$ cannot be obtained from which of the following reactions?

The reagents/chemicals $X$ and $Y$ that convert cyanobenzene to a Schiff's base are:

Enumerate different methods to prepare aldehyde compounds.