Correct increasing order of pKb values    in the above compounds is

A) I, II, III are aryl amines. In these amines the lone pair is involved in resonance. They are less basic ;As the number of benzene rings increases delocalization of lone pair increases, basic strength decreases.B) IV is a aryl alkyl amine in which the lone pair is localized. It is more basic; ∴ basic strength of IV > III > II > I;pkb of IV < III < II < I.