39. 已知①~④,以此判斷氧化劑的強弱?① A2+2D –→2A –+D2② B2+2D –→2B –+D2③ A2+2B –→無反應④ B2+2C –→無反應(A) A2 >B2 >C2 >D2 (B) A2 >C2 >D2 >B2(C) C2 >B2 >A2 >D2 (D) D2 >C2 >B2 >A2