Arrange the following in increasing order of basic strength

Options

A. `II lt I lt III lt IV`
B. `IV lt III lt II lt I`
C. `IV lt III lt I lt II`
D. `I lt II lt III lt IV`

Answer

D

Explanation

`(IV)` is most basic as it produces resonance stabilised conjugate acid after protonation at `sp^(2)` nitrogen. `III` is more basic than both `I` and `II` as carbonyl is shared by both nitrogen's lone pair in resonace which decreases the extent of delocalisation of nitrogen's lone pair. Between `I` and `II,III` is slightely more basic due to `+I` effect of `CH_(3)`.