Basic Doubt from Resonance

Why a, b and c are not resonance structures?

A and b are tautomers of each other

I know that, I want to know why they are not resonating structures

For resonance, the basic structure of compound must be same .
But , here in fig 1 H is attached with N
And in fig 2 H is attached with O

So basic structure is different and hence they can’t be resonance structures

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Resonance is the distribution of pi electrons through a conjugated system, only electrons. So, any nucleus shift is not allowed.

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