Consider the following reaction. The major product (P) formed is:

The reaction sequence proceeds as follows:

The reagent $\text{NaBH}_4$ is a mild reducing agent that selectively reduces the aldehyde group ($-\text{CHO}$) to a primary alcohol ($-\text{CH}_2\text{OH}$). The lactam (cyclic amide) ring remains unaffected.

Heating with aqueous $\text{NaOH}$ causes the base-catalyzed hydrolysis of the lactam ring. The amide bond breaks, forming a carboxylate salt ($-\text{COO}^-$) and a secondary amine ($-\text{NH}-$).

Acidification with $\text{H}_3\text{O}^+$ protonates the carboxylate ion to form a carboxylic acid ($-\text{COOH}$).

The final product is an open-chain amino acid derivative with the structure $\text{HOOC}-\text{CH}_2-\text{CH}_2-\text{CH}_2-\text{CH}_2-\text{NH}-\text{CH(CH}_3)-\text{CH}_2\text{OH}$. This matches the structure given in option (C).

Answer: