Hypervalent compound is (are) : 

Hypervalent molecule -

A molecule is considered hypervalent if it has one or more main group components that appear to have more than eight electrons in their valence shells.

Reason – 

A. Valence electrons present in ${\mathrm{SO}}_3^{2-}$ => 8, 

B. Available valence electrons in ${\mathrm{PO}}_4^{3-}$ => 10, 

C. Available valence electrons in ${\mathrm{SO}}_4^{2-}$ => 12, 

D. Present valence electrons in ${\mathrm{ClO}}_4^{-}$ => 14.