In which of the following case the $\mathrm{F}-\mathrm{Br}-\mathrm{F}$ angle is less than $90°$?

The shape of a molecule is determined by the arrangement that minimises the repulsion between the valence electron pairs around an atom, which is predicted by VSEPR. After lone pair/bond pair repulsion, all four planar bonds will $\mathrm{F}-\mathrm{Br}-\mathrm{F}$ decrease from $90°$ to $84.8°$. Therefore, in ${\mathrm{BrF}}_3$ and ${\mathrm{BrF}}_5$, there are no 90-degree $\mathrm{F}-\mathrm{Br}-\mathrm{F}$ angles.