$$M_3A_2$$ is a sparingly soluble salt of molar mass $$y$$ g mol$$^{-1}$$ and solubility $$x$$ g L$$^{-1}$$. The ratio of the molar concentration of the anion ($$A^{3-}$$) to the solubility product of the salt is

A

$$\frac{1}{54} \cdot \frac{y^4}{x^4}$$

B

$$\frac{y^5}{108x^4}$$

C

$$108 \cdot \frac{x^5}{y^5}$$

D

$$\frac{1}{108} \cdot \frac{y^4}{x^4}$$