Which of the following pairs does not represent resonating structures?

• A
  $CH_3-C(=O)-CH_3$ and $CH_3-C(OH)=CH_2$
• B
  
• C
  $CH_3-C(=O^{+}-H)-CH_3$ and $CH_3-C^{+}(OH)-CH_3$
• D
  $CH_2=C=O$ and $C^{-}H_2-C \equiv O^{+}$