What [CrO4] must be present in .00105 M AgNO3(aq) to just cause Ag2CrO4(s) to precipitate

Ksp for Ag2CrO4(s)=1.1e-12

A) >5.24e-10
B) >2.49e-7
C) >1.05e-9
D) >9.98e-7

When Ksp = Qsp (solubilty at equilibrium), the solution is saturated and with a little added CrO4 2-, Ag2CrO4 will ppt.

Ksp = 1.1x10^-12 = [Ag+]^2[CrO4 2-]
1.1x10^-12 = 4x^3
x = 6.5x10^-5M = [CrO4 2-]

Qsp = 1.1x10^-12 = [Ag+]^2[CrO4 2-]
with [Ag+] = 0.00105M, what is [CrO4 2-]
1.1x10^-12 = (0.00105)^2[CrO4 2-]
[CrO4 2-] = 9.98x10^-7M
any [CrO4 2-] > 9.98x10^-7M will cause a ppt of Ag2CrO4