The cationic part of ${\mathrm{I}}_2{\mathrm{O}}_6\left(s\right)$ has central iodine as :

The cationic part of ${\mathrm{I}}_2{\mathrm{O}}_6\left(s\right)$ has central iodine as $s{p}^2$ hybridized.

Trigonal hybridization is another name for ${\mathrm{sp}}^2$ hybridization. To create the new hybrid orbital known as ${\mathrm{sp}}^2$ one's' orbital and two 'p' orbitals of equal energy are mixed together. Trigonal symmetry was used to generate a combination of s and p orbitals, which are kept at ${120}^{\circ }$.

Hence, the option B is correct.