Calculate the value of the solubility product for magnesium carbonate knowing that its solubility is 1.8 x 10⁻⁴ mol/L.
A) 3.2 x 10⁻⁸
B) 3.6 x 10⁻⁴
C) 3.2 x 10⁻⁴
D) 1.8 x 10⁻⁸