A solution contains $0.010\mathrm{M}$ $\mathrm{Cl}{}^{-}$ and $0.010\mathrm{M}$ $\mathrm{CrO}{}_4{}^{2-}$. Solid $\mathrm{AgNO}{}_3$ is added without volume change. Given $K_{sp}(\mathrm{AgCl})=1.6\times 10^{-10}$ and $K_{sp}(\mathrm{Ag}{}_2\mathrm{CrO}{}_4)=1.9\times 10^{-12}$, the concentration of $\mathrm{Cl}{}^{-}$ remaining when $\mathrm{Ag}{}_2\mathrm{CrO}{}_4$ just begins to precipitate is

1. A$1.16\times 10^{-5}\mathrm{M}$
2. B$1.38\times 10^{-5}\mathrm{M}$
3. C$2.32\times 10^{-5}\mathrm{M}$
4. D$1.60\times 10^{-8}\mathrm{M}$