What is the difference between the resonance structures of $CH_3CH_2COO^{-}$ and $CH_3COOH$?

• A
  The resonance structures of $CH_3CH_2COO^{-}$ involve charge separation,while $CH_3COOH$ does not.
• B
  The resonance structures of $CH_3CH_2COO^{-}$ are equivalent,whereas those of $CH_3COOH$ are non-equivalent.
• C
  The resonance structures of $CH_3CH_2COO^{-}$ are non-equivalent,while those of $CH_3COOH$ are equivalent.
• D
  There is no difference in the nature of resonance structures for these two species.