To solve this problem, we need to understand the reaction of amines with Hinsberg's reagent.$\newline$Hinsberg's reagent is benzene sulfonyl chloride (C$_6$H$_5$SO$_2$Cl).$\newline$It is used to distinguish between primary, secondary, and tertiary amines.$\newline$• Primary amines react with Hinsberg's reagent to form a sulfonamide, which is soluble in alkali.$\newline$• Secondary amines form a sulfonamide that is insoluble in alkali.$\newline$• Tertiary amines do not react with Hinsberg's reagent.$\newline$Let's analyze the options:$\newline$Option 1: The compound is a nitro compound, not an amine.$\newline$Option 2: The compound is a secondary amine (CH$_3$CH$_2$NHCH$_3$).$\newline$Option 3: The compound is a primary amine (CH$_3$CH$_2$NH$_2$).$\newline$Option 4: The compound is a tertiary amine (CH$_3$CH$_2$N(CH$_3$)CH$_2$CH$_3$).$\newline$The primary amine (Option 3) will react with Hinsberg's reagent to form a sulfonamide that dissolves in alkali.$\newline$Therefore, the correct option is Option 3.