Which one(s) of the following structures cannot represent resonance forms for ${\mathrm{N}}_2\mathrm{O}$ (diamagnetic)?

(P) $:\ddot{\mathrm{N}}=\mathrm{N}=\ddot{\mathrm{O}}$ (Q) $:\mathrm{N}\equiv \mathrm{N}-\ddot{\mathrm{O}}:$

(R) $\ddot{\mathbf{:}\mathbf{N}}-\mathbf{N}\equiv \mathbf{O}\mathbf{:}$ (S) $:\ddot{\mathrm{N}}=\mathrm{O}=\ddot{\mathrm{N}}:$ (T) $:\dot{\mathrm{N}}=\mathrm{N}=\dot{\mathrm{O}}:$

In R.S., position of atoms do not change. Also, number of paired and unpaired$e^{-}$ do not change. Hence, R, S and T structures cannot represent resonance forms for ${\mathrm{N}}_2\mathrm{O}$ (diamagnetic).