The stoichiometry and solubility product of a salt with the solubility curve given below is, respectively:

A

X$$_2$$Y, $$2 \times 10^{-9}$$ M$$^3$$

B

XY$$_2$$, $$4 \times 10^{-9}$$ M$$^3$$

C

XY$$_2$$, $$1 \times 10^{-9}$$ M$$^3$$

D

XY, $$2 \times 10^{-6}$$ M$$^3$$