Treat NO in nitroprusside as $\mathrm{NO}{}^{+}$ and CO as neutral. Select ALL correct name-oxidation-state pairs.

1. A$\mathrm{Na}{}_2[\mathrm{Fe}(\mathrm{CN}){}_5\mathrm{NO}]$: sodium pentacyanidonitrosylferrate(II)
2. B$\mathrm{K}{}_4[\mathrm{Fe}(\mathrm{CN}){}_6]$: potassium hexacyanidoferrate(II)
3. C$\mathrm{K}{}_3[\mathrm{Fe}(\mathrm{CN}){}_6]$: potassium hexacyanidoferrate(II)
4. D$\mathrm{Ni}(\mathrm{CO}){}_4$: tetracarbonylnickel(0)