In which of the following molecules does the $\sigma 2p_z$ molecular orbital lie higher in energy than the $\pi 2p_x$ and $\pi 2p_y$ orbitals?

For molecules up to $\mathrm{N}{}_2$, 2s-2p mixing raises $\sigma 2p_z$ above the $\pi 2p$ pair. For $\mathrm{O}{}_2$ and beyond, the mixing is weak and $\sigma 2p_z$ lies below $\pi 2p$. Among the options only $\mathrm{N}{}_2$ has the mixed ordering.