Answer
The correct answer is (b)
Work Step by Step
In $CO_3^{2-}$. the double bond between $C$ and $O$ resonates between the three oxygen atoms. This resonance is correctly depicted in option (b)
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.