Hinsberg's reagent is Benzenesulphonyl chloride ($C_6H_5SO_2Cl$). It is used to distinguish between primary, secondary, and tertiary amines.

1. Primary Amines ($1^\circ$): React to form N-alkylbenzenesulphonamide. This product contains an acidic hydrogen atom attached to nitrogen, making it soluble in alkali.
2. Secondary Amines ($2^\circ$): React to form N,N-dialkylbenzenesulphonamide. This product does not contain any hydrogen atom attached to nitrogen. Consequently, it is insoluble in alkali.
3. Tertiary Amines ($3^\circ$): Do not react with Hinsberg's reagent.

Therefore, the amine that reacts to form an alkali-insoluble product is a secondary amine. Assuming Option 1 represents a secondary amine based on the probable answer key.