In the $HCOO^{-}$ anion,the two carbon-oxygen bonds are found to be of equal length. What is the reason for this?

• A
  The anion $HCOO^{-}$ has two equivalent resonance structures.
• B
  The anion is formed after the removal of a proton from the acid molecule.
• C
  The electronic orbitals of the carbon atom are in hybridization.
• D
  The $C=O$ bond is weaker than the $C-O$ bond.