CO2, NO, SO3
NCl3, BCl3, SO3
NH3, SO3, CO2
BF3, NF3, CO2
The group having triangular planar structures is CO2, NO, SO3.
In CO2, the C atom is sp hybridized. This results in a linear structure, not a triangular planar structure.
In NO, the N atom is sp hybridized. This results in a linear structure, not a triangular planar structure.
In SO3, the S atom is sp2 hybridized. This results in a triangular planar structure.
Therefore, only SO3 has a triangular planar structure among the given options. The other options are incorrect because they include molecules that do not have triangular planar structures.