Which one of the following elements has the highest ionisation energy?

• A

  $\left[\mathrm{Ne}\right]3s^{2}3p^1$

• B

  $\left[\mathrm{Ne}\right]3s^{2}3p^3$

• C

  $\left[\mathrm{Ne}\right]3s^{2}3p^2$

• D

  $\left[\mathrm{Ar}\right]3d^{10}4s^{2}4p^2$