Correct Answer - D
I and III are `2^(@)` amines as such these will be most basic. Out of these I is more basic than III. It is due to the presence of highly electronegative 0 in the ring in III. In II, N is `sp^(2)` hybridised with lone pair in `sp^(2)`-hybridised orbital. As such lone pair is available and this makes it basic. In IV, N is `sp^(2)`-hybridised with lone pair in unhybridised p- orbital. This lone pair is delocalised over the ring and such is not easily available, thus making it least basic.
