$KF$ combines with $HF$ to form $KHF_2$. The compound contains the species

• A
  $K^{+}$,$F^{-}$ and $H^{+}$
• B
  $K^{+}$,$F^{-}$ and $HF$
• C
  $K^{+}$ and $[HF_2]^{-}$
• D
  $[KHF]^{+}$ and $F^{-}$