106ohh yes,
See, V will be least stable as it is phenyl carbocation.
I and IV have resonance possible so are most stable and as O is more electronegative than N, +ve charge on N is relatively more stable than that on O. So IV is more stable than I.
in III and II, O is EWG as it is electronegative, so farther the EWG, more is the stability of the +ve charge. So III>II
In I and IV resonance dominates inductive effect