Correct Answer - D
Thinking process This type of problem can be solved by application of electron-withdrawing and electron donating group.
In `III, -CH_(3)` group is an electron donating and o/p directing group which increase the electron density on benzene ring at ortho or para position while in `II,-NO_(2)` group is an electron withdrawing group which decrease the electron density on benzene ring. Hence, the III is more basic than II. In I, there is no substituent attached, due to which I is more basic than II and less basic than III.
Therefore, the correct order of basic strength of above compounds is `II lt I lt III`.
