Which of the following ions are present in the anhydrous mixture of $KF$ and $HF$?

• A
  ${K^ + }, {H^ + }, {F^ - }$
• B
  ${(KF)^ + }, {(HF)^ - }$
• C
  ${KH^ + }, {F^ - }$
• D
  ${K^ + }, HF_2^ - $