Conjugate base for Bronsted acids $H_{2}O$ and $HF$ are

• A
  $OH^{-}$ and $H_{2}F^{+}$ respectively
• B
  $H_{3}O^{+}$ and $F^{-}$ respectively
• C
  $OH^{-}$ and $F^{-}$ respectively
• D
  $H_{3}O^{+}$ and $H_{2}F^{+}$ respectively