A white sodium salt dissolves readily in water to give a solution which is neutral to litmus. When silver nitrate solution is added to the aforementioned solution, a white precipitate is obtained which does not dissolved in dil. nitric acid. The anion is :
A. `CO_(3)^(2-)`
B. `SO_(4)^(2-)`
C. `S^(2-)`
D. `Cl^(-)`