The correct order of increasing s-character (in percentage) in the hybrid orbitals in below molecules /ions is (assume all hybrid orbitals are exactly equivalent) :

$\begin{array}{l}\underset{\mathrm{I}}{{\mathrm{CO}}_3^{2-}}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\underset{\mathrm{II}}{{\mathrm{XeF}}_4}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\underset{\mathrm{III}}{{\mathrm{I}}_3^{-}}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\underset{\mathrm{IV}}{{\mathrm{NCl}}_3}\hspace{0.25em}\underset{\mathrm{V}}{\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}{\mathrm{BeCl}}_2}\end{array}$

Correct option is A

$\begin{array}{l}\underset{{\mathrm{sp}}^2}{{\mathrm{CO}}_3^{2-}\hspace{0.25em}}\hspace{0.25em}\underset{{\mathrm{sp}}^3{\mathrm{d}}^2}{\hspace{0.25em}\hspace{0.25em}{\mathrm{XeF}}_4}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\underset{{\mathrm{sp}}^3\mathrm{d}}{{\mathrm{I}}_3^{-}}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\underset{{\mathrm{sp}}^3}{{\mathrm{NCl}}_3}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\underset{\mathrm{sp}}{{\mathrm{BeCl}}_2}\end{array}$

The correct order of increasing s−character (in percentage) in the hybrid orbitals of following molecules/ions is:

$\text{ (I) }{\mathrm{CO}}_3^{2-}$       $\mathrm{C}$  

undergoes ${\mathrm{sp}}^2$

$\text{ (II) }{\mathrm{XeF}}_4$      $\mathrm{Xe}$ 

undergoes ${\mathrm{sp}}^3{\mathrm{d}}^2$

$\text{ (III) }{\mathrm{I}}_3^{-}$           $\mathrm{I}$

undergoes  ${\mathrm{sp}}^3\mathrm{d}$

$\text{ (IV) }{\mathrm{NCl}}_3$     $\mathrm{N}$  

undergoes ${\mathrm{sp}}^3$

$\text{ (V) }{\mathrm{BeCl}}_2$     $\mathrm{Be}$ 

undergoes $\mathrm{sp}$

S-character in hybrid orbitals increases as the number of p orbitals and d orbitals in the hybridization.

So the correct order of S-character in hybrid orbitals is $\mathrm{sp}>{\mathrm{sp}}^2>{\mathrm{sp}}^3>{\mathrm{sp}}^3\mathrm{d}>{\mathrm{sp}}^3{\mathrm{d}}^2$

So the correct option is $\mathrm{II}<\mathrm{III}<\mathrm{IV}<\mathrm{I}<\mathrm{V}$