For which one of the following, Bohr model is not valid?

The Bohr model is applicable only to single-electron species (hydrogenic atoms).Hydrogen: $1e^{-}$$H{e}^{+}$: $2-1=1e^{-}$ Deuteron ($H$ isotope): $1e^{-}$$N{e}^{+}$: $10-1=9e^{-}$. Bohr model is not valid for multi-electron atoms.