KF combines with HF to form ${\mathrm{KHF}}_2$. The compound contains the species

The fluoride ion, by process of hydrogen bonding, forms the anion ${\mathrm{HF}}_2^{-}$.
The compound is written as ${\mathrm{K}}^{+}{\left[{\mathrm{HF}}_2\right]}^{-}$

${\mathrm{K}}^{+}{[\mathrm{F}-\mathrm{H}-\mathrm{F}]}^{-}$

Hence, the correct option is (C) .