The major product of the following reaction is

The correct structure of product $A$ formed in the following reaction:
$PhCHO + PhCHO \xrightarrow[in\, D_2O]{NaOD} A + PhCOO^{-}$
($Ph$ is $-C_6H_5$)

Match the items in List-$I$ with the items in List-$II$ and select the correct code:

List-$I$	List-$II$
$A$. Tollen's reagent	$I$. Para-rosaniline + $SO_2$
$B$. Schiff's reagent	$II$. Rochelle salt + $aq. NaOH$
$C$. Rosenmund reduction	$III$. Ammoniacal silver nitrate
$D$. Fehling solution $B$	$IV$. $Pd + BaSO_4$

The reaction of $5-$methylenecyclohex$-2-$enone with $2$ equivalents of $HBr$ yields which of the following products?

$CH_3CHO \xrightarrow{LiAlH_4} CH_3CH_2OH$
Which nucleophile is added in this reaction?

Identify the product of the following reaction: $Formaldehyde + Benzaldehyde \xrightarrow[H_3O^{+}]{conc. NaOH} \text{product}$