Hybridization of triply bonded carbons, carbon–carbon triple bond length and bond strength of carbon-carbon triple bond are 

Given data:

It is given to identify the hybridization of triply bonded carbons, carbon–carbon triple bond length and bond strength of carbon-carbon triple bond. 

Formula/concept: Alkynes 

Detailed solution:

The carbon-carbon triple bond is generally called alkynes which is represented as $HC\equiv CH$. The carbon here are $sp$ - hybridized. Triple bond is the shortest and hence, difficult to break. The bond length of this triple bond is1. $20A°$. Alkynes with $sp$-hybridization possess a bond strength of 825 ${\mathrm{kJMol}}^{-1}$.

Therefore, option (C) is correct.