Which of the $C - C$ bond is strongest?

The correct order of increasing $s$-character (in percentage) in the hybrid orbitals of the following molecules/ions is: $(I) \, CO_3^{2-}$,$(II) \, XeF_4$,$(III) \, I_3^-$,$(IV) \, NCl_3$,$(V) \, BeCl_2$.

The hybridisations of $N$,$C$ and $O$ shown in the following compound are:

In $CH_4$ molecule,the hydrogen atoms around carbon are arranged as

Among the following transformations,the hybridisation of the central atom remains unchanged in

Identify the molecules which have $sp$-hybridised carbon$(s)$ from the list given below:
$I$. Ethane nitrile $(CH_3CN)$
$II$. Buta$-1,3-$diene $(CH_2=CH-CH=CH_2)$
$III$. Propan$-1,2-$diene $(CH_2=C=CH_2)$
$IV$. Ethyne $(HC \equiv CH)$
$V$. Benzene $(C_6H_6)$