The correct statement /s about `SO_(4)^(-2)` ion is/are
(A) It is tetrahedral
(B) All the `S-O` bond lengths are equal
(C) It contains four `sigma` bonds between 'S' and 'O' atoms,two ' `pi` ' bonds delocalised over the 'S' and four 'O' atoms
(D) All the S - O bonds have the bond order 1.5