Which molecule/ion out of the following does not contain unpaired electrons?

The electronic configuration of the given molecules are

${\mathrm{N}}_2^{+}=13\text{ electrons }\mathrm{\sigma }1{\mathrm{s}}^2,{\mathrm{\sigma }}^{*}1{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{s}}^2,{\mathrm{\sigma }}^{*}2{\mathrm{s}}^2,\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^2$

$=\mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^2,\mathrm{\sigma }2{\mathrm{p}}_{\mathrm{z}}^1$

It has one unpaired electron

${\mathrm{O}}_2=16\text{ electrons }\mathrm{\sigma }1{\mathrm{s}}^2,{\mathrm{\sigma }}^{*}1{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{s}}^2,{\mathrm{\sigma }}^{*}2{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{p}}_{\mathrm{z}}^2$$\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^2\approx \mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^2,{\mathrm{\pi }}^{*}2{\mathrm{p}}_{\mathrm{x}}^1\approx {\mathrm{\pi }}^{*}2{\mathrm{p}}_{\mathrm{y}}^1$

${\mathrm{O}}_2$ has two unpaired electrons.

${\mathrm{O}}_2^{2-}=18\text{ electrons }{\mathrm{\sigma ls}}^2,\stackrel{*}{\mathrm{O}}1{ \mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{s}}^2,\stackrel{*}{\mathrm{\sigma }}2{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{p}}_{\mathrm{z}}^2$$\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^2\approx \mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^2,{\mathrm{\pi }}^{*}2{\mathrm{p}}_{\mathrm{x}}^2\approx \mathrm{\pi }*2{\mathrm{p}}_{\mathrm{y}}^2$

Thus, ${\mathrm{O}}_2^{2-}$ has no unpaired electrons.

${\mathrm{B}}_2=10\text{ electrons }{\mathrm{\sigma ls}}^2{,}^{*}{\mathrm{\sigma }}^2{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{s}}^2,\stackrel{*}{\mathrm{\sigma }}2{\mathrm{s}}^2,\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^1\approx \mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^1$

Thus, ${\mathrm{B}}_2$ has two unpaired electrons.