Linear and planar structures

The answer is incorrect.

Firstly, the answer attempted to explain the stability in terms of hybridization. Actually, hybridization is a 「theory」to explain the shape of a molecule, but not the stability of the molecule.
If a molecule exists, its shape is explained by the theory of hybridization.
If a molecule does not exist, the reason is explained in terms of energy and steric hindrance.

Secondly, theory of hybridization is only applied to the central atoms of molecules, but not the terminal atoms. S=O molecule (if exists) is diatomic, both S and O atoms are in terminal positions. Therefore, don’t apply theory of hybridization on it. It is never found in any textbook that uses theory of hybridization for diatomic molecules such as O2, HCl, etc. Theory of hybridization is only applied to the central atoms of molecules consisting with 3 or more atoms.