A arrange the following resonating structures in the order of decreasing stability
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Explanation

Structures(I) and (II) have greater number of covalent bonds hence, these are more stable than either (III) or (IV) Furthermore, between I and II, structure I has no formal charges and hence is more stable than structure (II)
(b) Structure (IV) is less stable than (III) because in (IV) the poitive charge is on oxygen, which is a more `EN` atom than carbon on which positive charge is present in (III) Thus the order of stability is `IgtIIgtIIIgtIV` .