Assign $A, B, C, D$ from the given type of reaction.
$Fe^{2+}(aq.) + Cr_2O_7^{2-}(aq.) + H^+(aq.) \longrightarrow Fe^{3+}(aq.) + Cr^{3+}(aq.) + H_2O(l)$

• A
  $A$. for disproportionation reaction.
• B
  $B$. for comproportionation reaction.
• C
  $C$. for either intermolecular redox reaction or displacement reaction.
• D
  $D$. for either thermal combination redox reaction or thermal decomposition redox reaction.