Use the following rule set. Slater's rules: write the configuration in groups $(1s)(2s,2p)(3s,3p)(3d)(4s,4p)(4d)(4f)(5s,5p)\dots$ For an electron in an $ns$ or $np$ group, every other electron in the same group contributes $0.35$ ($0.30$ for the $1s$ group), every electron in the $(n-1)$ shell contributes $0.85$, every electron in the $(n-2)$ or lower shells contributes $1.00$, and electrons in groups to the right contribute $0$. For an electron in an $nd$ or $nf$ group, every other electron in the same group contributes $0.35$, every electron in all groups to its left contributes $1.00$, and groups to the right contribute $0$. $Z^{\ast }=Z-S$. The Slater orbital energy is $E=-13.6(Z^{\ast }{)}^2/(n^{\ast }{)}^2\mathrm{eV}$ with $n^{\ast }=1$ for $n=1$. The magnitude of the energy of a $1s$ electron in $\mathrm{Li}{}^{+}$ ($Z=3$, configuration $1s^2$) is:

1. A122.4$\mathrm{eV}$
2. B95.5$\mathrm{eV}$
3. C99.1$\mathrm{eV}$
4. D62.9$\mathrm{eV}$