Which of these reagents would accomplish the following reduction?
$NC-CH_2-CO-CH_2-CH=CH_2 \to NC-CH_2-CH(OH)-CH_2-CH=CH_2$

$A$ mixture of benzaldehyde and formaldehyde on heating with aqueous $NaOH$ solution gives:

In the given reaction $CH_3-CH_2-C(=O)-CH_2-COOC_2H_5$ $\xrightarrow{[X]} (A)$ $\xrightarrow{(i) LiAlH_4, (ii) H_2O/H^{+}} CH_3-CH_2-C(=O)-CH_2-CH_2OH + C_2H_5OH$,$[X]$ will be:

What will be the major product?

Calcium butanoate on heating followed by treatment with $1,2-$ethanediol in the presence of a catalytic amount of an acid,produces a major product which is

An organic compound $(A)$ with molecular formula $C_8H_8O$ forms an orange-red precipitate with $2,4-DNP$ reagent and gives a yellow precipitate on heating with iodine in the presence of sodium hydroxide. It neither reduces Tollens' or Fehlings' reagent,nor does it decolourise bromine water or Baeyer's reagent. On drastic oxidation with chromic acid,it gives a carboxylic acid $(B)$ having molecular formula $C_7H_6O_2$. Identify the compounds $(A)$ and $(B)$ and explain the reactions involved.