For the precipitation reaction of $Ag^{+}$ ions with $NaCl$,which of the following statements is correct?

How many grams of $CaC_2O_4$ (molecular weight $= 128$) on dissolving in $1 \ L$ of distilled water will give a saturated solution? $[K_{sp}(CaC_2O_4) = 2.5 \times 10^{-9} \ mol^2 L^{-2}]$

Find the solubility of $PbI_2$ if its solubility product is $7.0 \times 10^{-9}$.

If the concentration of $Ag^{+}$ ions in the saturated solution of $Ag_2CO_3$ is $1.20 \times 10^{-4} \ mol \ L^{-1}$,then find the solubility product of $Ag_2CO_3$.

The best explanation for the solubility of $MnS$ in dil. $HCl$ is that

At $298 \ K$ temperature,the $K_{sp}$ of $CaF_2$ is $1.7 \times 10^{-10}$. If a person drinks $2.5 \ L$ of $CaF_2$ saturated water daily,how many grams of $CaF_2$ are present in the water consumed? (Molecular mass of $CaF_2$ is $78 \ g \ mol^{-1}$)