The K _sp for Silver Bromide (AgBr) Is 7

The K _sp for silver bromide (AgBr) is 7.7×10 ^{- 13}. What is the solubility of this salt in pure water?

A) 8.8×10 ^{- 7} M
B) 3.2×10 ^{- 5} M
C) 2.3×10 ^{- 3} M
D) 14 M
E) 0.46 M