In the reaction $HCl + H_2O \rightleftharpoons H_3O^{+} + Cl^{-}$,which of the following statements is correct?

• A
  $H_2O$ is the conjugate base of $HCl$ acid
• B
  $Cl^{-}$ is the conjugate base of $HCl$ acid
• C
  $Cl^{-}$ is the conjugate acid of $H_2O$ base
• D
  $H_3O^{+}$ is the conjugate base of $HCl$