Which of the following statements are correct?
I. Bond order of NO is 2.5
II. Bond order of NO⁺ is 3.0
III. Bond order of O₂ is 1.5
IV. Bond order of CO is 3.0

$\begin{array}{l}\mathrm{NO}=15=\mathrm{\sigma }1{\mathrm{s}}^2,{\mathrm{\sigma }}^{\ast }1{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{s}}^2,{\mathrm{\sigma }}^{\ast }2{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{p}}_{\mathrm{z}}^2,\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^2=\mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^2,{\mathrm{\pi }}^{\ast }2{\mathrm{p}}_{\mathrm{x}}^1={\mathrm{\pi }}^{\ast }2{\mathrm{p}}_{\mathrm{y}}^0\\ {\mathrm{NO}}^{+}=14=\mathrm{\sigma }1{\mathrm{s}}^2,{\mathrm{\sigma }}^{\ast }1{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{s}}^2,{\mathrm{\sigma }}^{\ast }2{\mathrm{s}}^2,\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^2=\mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^2,\mathrm{\sigma }2{\mathrm{p}}_{\mathrm{z}}^2\\ {\mathrm{O}}_2=16=\mathrm{\sigma }1{\mathrm{s}}^2,{\mathrm{\sigma }}^{\ast }1{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{s}}^2,{\mathrm{\sigma }}^{\ast }2{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{p}}_{\mathrm{z}}^2,\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^2=\mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^2,{\mathrm{\pi }}^{\ast }2{\mathrm{p}}_{\mathrm{x}}^1={\mathrm{\pi }}^{\ast }2{\mathrm{p}}_{\mathrm{y}}^1\\ \mathrm{CO}=14=\mathrm{\sigma }1{\mathrm{s}}^2,{\mathrm{\sigma }}^{\ast }1{\mathrm{s}}^2,\mathrm{\sigma }2{\mathrm{s}}^2,\mathrm{\pi }2{{\mathrm{p}}_{\mathrm{x}}}^2=\mathrm{\pi }2{{\mathrm{p}}_{\mathrm{y}}}^2,\mathrm{\sigma }2{{\mathrm{p}}_{\mathrm{z}}}^2,{\mathrm{\sigma }}^{\ast }2{{\mathrm{ps}}^2}^2\end{array}$
$\begin{array}{l}\mathrm{a}\therefore \left\{\begin{array}{ll}\mathrm{NO}& 2.5\\ {\mathrm{NO}}^{+}& 3\\ \mathrm{CO}& 3\end{array}\right\}\\ \text{ B.O }=\frac{10-5}{2}=2.5\\ \text{ B.O }=\frac{10-4}{2}=3\\ \text{ B.O }=\frac{10-6}{2}=2\\ \text{ B.O }=\frac{10-4}{2}=3\end{array}$