The Molar Solubility of SrF₂ in Water Is 8

The molar solubility of SrF₂ in water is 8.8×10 ^{- 4} M. What is the solubility product constant, K _sp, for this substance?

A) K _sp = 6.81×10 ^{- 10}
B) K _sp = 2.73×10 ^{- 9}
C) K _sp = 7.74×10 ^{- 7}
D) K _sp = 1.55×10 ^{- 6}
E) K _sp = 2.64×10 ^{- 3}