Which one of the following statements is correct?

$\displaystyle \mathrm{Ce}^{4+}$ is more stable than $\displaystyle \mathrm{Ce}^{3+}$ due to $\displaystyle 4 \mathrm{f}^0$ configuration.

$\displaystyle \mathrm{Eu}^{2+}$ is more stable than $\displaystyle \mathrm{Eu}^{3+}$ due to $\displaystyle 4 \mathrm{f}^7$ configuration.

$\displaystyle \mathrm{Ce}^{4+}$ is an oxidant and $\displaystyle \mathrm{Eu}^{2+}$ is a reducing agent.

$\displaystyle \mathrm{Ce}^{3+}$ and $\displaystyle \mathrm{La}^{3+}$ salts are colored and paramagnetic.