The correct increasing order of basic strength for the following compounds is:

Basic strength of amines depends on the availability of the lone pair on Nitrogen.(II) $p$ -Nitroaniline: The $-{\text{NO}}_2$ group is strongly electron-withdrawing ($-M$ and $-I$ effect), which significantly reduces the electron density on Nitrogen, making it the weakest base.(I) Aniline: Standard reference.(III) $p$ -Toluidine: The $-{\text{CH}}_3$ group is electron-donating ($+I$ and hyperconjugation), which increases the electron density on Nitrogen, making it the strongest base among the three.Increasing order: II (Nitro) < I (Aniline) < III (Toluidine).