Write the rules to decide the relative stability of different resonance structures.

(N/A) $(i)$ Among the resonance structures,the one which has a greater number of covalent bonds and all atoms with a complete octet of electrons (except hydrogen,which has a duplet) is more stable.
$(ii)$ Among the resonance structures,those with less separation of opposite charges are more stable.
$(iii)$ $A$ negative charge on a more electronegative atom and a positive charge on a more electropositive atom contribute to greater stability.
$(iv)$ Resonance structures with more dispersal of charge are more stable than others.