For saturated $\mathrm{Ca}(\mathrm{OH}){}_2$ at 298 K with $K_{sp}=4.0\times 10^{-6}$ (no other source of $\mathrm{OH}{}^{-}$ or $\mathrm{Ca}{}^{2+}$, activities ignored), choose the correct statement(s).

1. AIn pure water $[\mathrm{OH}{}^{-}]=2.0\times 10^{-2}\mathrm{M}$
2. BIn $0.010\mathrm{M}$ $\mathrm{NaOH}$ the solubility is about $7.0\times 10^{-3}$ $\mathrm{M}$
3. CIn $0.010\mathrm{M}$ $\mathrm{CaCl}{}_2$ the solubility is about $2.3\times 10^{-2}$ $\mathrm{M}$
4. DThe solubility in $0.010\mathrm{M}$ $\mathrm{NaOH}$ is greater than in pure water