Which one of the following statements is true about the structure of ${\text{CO}}_{\text{3}}^{\text{2-}}$ ion ?

All three C-O bonds are equal in  length with a bond order in between 1 and 2.

it can be explained by considering ${\text{sp}}^{\text{3}}$ hybridisation.

Out of the three C-O bonds , two are longer and one is shorter.

It has three sigma and one pi bonds.