Final answer:
Carbon dioxide (CO₂) option (a) exhibits sp hybridization, where the central carbon atom forms two double bonds with oxygen atoms, resulting in a linear molecule structure.
Step-by-step explanation:
The question is regarding the sp hybridization of molecules. Based on information provided in the reference, carbon undergoes sp hybridization when it forms two sigma (σ) bonds, typically with linear molecular geometry. Out of the options given, carbon dioxide (CO₂) exhibits sp hybridization.
This is evident from the linear structure of CO₂, where the carbon atom forms two double bonds with oxygen atoms, each consisting of one sigma and one pi (π) bond. This is supported by the change from sp² hybridization in carbonate ion (CO₃²-) to sp hybridization in CO₂.