Which one of the following molecules is expected to exhibit diamagnetic behaviour?

The electronic configuration of the given molecules are

$\begin{array}{l}{\mathrm{C}}_2\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\left(\sigma 2\mathrm{s}{)}^2\right(\sigma \ast 2\mathrm{s}{)}^2{\left(\pi 2{\mathrm{p}}_x\right)}^2{\left(\pi 2{\mathrm{p}}_y\right)}^2\\ {\mathrm{N}}_2\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\left(\sigma 2\mathrm{s}{)}^2\right(\sigma \ast 2\mathrm{s}{)}^2{\left(\pi 2{\mathrm{p}}_x\right)}^2{\left(\pi 2{\mathrm{p}}_y\right)}^2{\left({\sigma }^{\ast }2{\mathrm{p}}_z\right)}^2\\ {\mathrm{O}}_2\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\left(\sigma 2\mathrm{s}{)}^2\right(\sigma \ast 2\mathrm{s}{)}^2{\left(\sigma 2{\mathrm{p}}_z\right)}^2{\left(\pi 2{\mathrm{p}}_x\right)}^2{\left(\pi 2{\mathrm{p}}_y\right)}^2{\left(\pi \ast 2{\mathrm{p}}_x\right)}^1{\left({\pi }^{\ast }2{\mathrm{p}}_y\right)}^{\mathrm{\prime }}\\ {\mathrm{S}}_2\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\left(\sigma 3\mathrm{s}{)}^2\right(\sigma \ast 3\mathrm{s}{)}^2{\left(\pi 3{\mathrm{p}}_x\right)}^2{\left(\pi 3{\mathrm{p}}_y\right)}^2{\left({\sigma }^{\ast }3{\mathrm{p}}_z\right)}^2{\left(\pi \ast 3{\mathrm{p}}_x\right)}^1{\left({\pi }^{\ast }3{\mathrm{p}}_y\right)}^{\mathrm{\prime }}\end{array}$

The molecules ${\mathrm{C}}_2$ and ${\mathrm{N}}_2$  do not possess unpaired electrons. Hence, these are expected to exhibit diamagnetic behaviour.