The polymer obtained from the following reactions is:

1. Step 1: Diazotization and Substitution

   Treatment of the primary aliphatic amine ($$-\text{NH}_2$$) with nitrous acid ($$\text{NaNO}_2 / \text{H}_3\text{O}^\oplus$$) converts it into a highly unstable diazonium salt, which decomposes immediately in the aqueous medium to form a hydroxyl ($$-\text{OH}$$) group:

   $$\text{HOOC--}(\text{CH}_2)_4\text{--NH}_2 \xrightarrow{\text{NaNO}_2/\text{H}_3\text{O}^\oplus} \text{HOOC--}(\text{CH}_2)_4\text{--OH}$$



2. Step 2: Condensation Polymerization

   Heating this bifunctional $\omega$-hydroxy acid monomer initiates self-esterification (condensation polymerization) accompanied by the continuous loss of water ($$\text{H}_2\text{O}$$) molecules, yielding a linear polyester chain:

   $$n\,\text{HOOC--}(\text{CH}_2)_4\text{--OH} \longrightarrow \left[\text{--O--}(\text{CH}_2)_4\text{--C}(=\text{O})\text{--}\right]_n + n\,\text{H}_2\text{O}$$

Conclusion:

The conversion of the amine into an alcohol yields a hydroxy acid monomer that polymerizes into a polyester structure rather than a polyamide.

Answer: Option showing the polyester repeating unit: $$\left[\text{--O--}(\text{CH}_2)_4\text{--C}(=\text{O})\text{--}\right]_n$$