A \( \operatorname{Ar}(18)-1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} \)
B \( \mathrm{K}(19)-[\mathrm{Ar}] 4 \mathrm{~s}^{1} \)
C \( \mathrm{Fe}(26)-[\mathrm{Ar}] 4 \mathrm{p} \)
D \( \mathrm{Cu}(29)-[\mathrm{Ar}] 3 \mathrm{~d}^{10} 4 \mathrm{~s}^{2} \)