d
\(\mathrm{CN}^{-}, \mathrm{CO}\) and \(\mathrm{NO}^{+}\) are isoelectronic with 14 electrons each and there is no unpaired electrons in the MO configuration of these species.

So these are diamagnetic. \(\mathrm{O}_{2}^{*}\) is paramagnetic due to the presence of one unpaired electron.

\(\left(\mathrm{CN}^{-}, \mathrm{CO}, \mathrm{NO}^{+}\right) 14=\sigma \mathrm{s}^{2}, \sigma^{*} \mathrm{L}^{2}, \sigma 2 s^{2}, \sigma^{*} 2 s^{2} \sigma 2 p_{x}^{2}\)

\(\pi 2 p_{y}^{2} \approx \pi 2 p_{z}^{2} \quad\) (No unpaired electron, diamagnetic)

\(\mathrm{O}_{2}^{-}=\sigma \mathrm{s}^{2}, \sigma^{*} 1 s^{2}, \sigma 2 s^{2}, \sigma^{*} 2 s^{2}, \sigma 2 p_{x}^{2}\)

\(\pi 2 p_{x}^{2} \approx \pi 2 p_{z}^{2}, \pi^{*} 2 p_{y}^{2}=\pi^{*} 2 p_{z}^{1}\)

(one unpaired electron, paramagnetic)