The solubility product of a salt having general formula MX2 in water is : 4 × 10⁻¹². The concentration of M²⁺ ions in the aqueous solution of the saltis
A 2.0 ×10⁻⁶ M
B 1.0×10⁻⁴ M
C 1.6 ×10⁻⁴ M
D 4×10⁻¹⁰ M