A yellow acidic solution of $\mathrm{Ce}{}^{4+}$ is treated with excess $\mathrm{Fe}{}^{2+}$ in dilute sulfuric acid. The cerium species present at the end, and its magnetic character, are

1. A$\mathrm{Ce}{}^{4+}$ with $4f^0$; unchanged
2. B$\mathrm{Ce}{}^{3+}$ with $4f^0$; diamagnetic
3. C$\mathrm{Ce}{}^{3+}$ with $4f^1$; paramagnetic with one unpaired electron
4. D$\mathrm{Ce}{}^{2+}$ with $4f^2$; paramagnetic with two unpaired electrons