What is the number of unpaired electron(s) in the highest occupied molecular orbital of the following species: \( \mathrm{N_2} \) ; \( \mathrm{N_2^+} \) ; \( \mathrm{O_2} \) ; \( \mathrm{O_2^+} \) ?
\( 2, 1, 2, 1 \)
\( 0, 1, 0, 1 \)
\( 0, 1, 2, 1 \)
\( 2, 1, 0, 1 \)