$BaCl_2$ solution gives a white ppt. with a solution of a salt, which dissolves in dil. HCl with the evolution of a colourless, pungent smelling gas. The acid radical in the salt is

Question

(a) $SO_4^{2-}$
(b) $HSO_4^-$
(c) $SO_3^{2-}$
(d) $CO_3^{2-}$