Which one of the following represents the electronic configuration of the most electropositive element

• A

  $\left[\mathrm{He}\right]2s^1$

• B

  $\left[Xe\right]6s^1$

• C

  $\left[\mathrm{He}\right]2{\mathrm{s}}^2$

• D

  $\left[Xe\right]6s^2$