Carbon dioxide is passed continuously for a long time through clear lime water. The milkiness that first appears later disappears because

1. A$\mathrm{CaCO}{}_3$ reacts with water to give $\mathrm{CaO}$
2. B$\mathrm{CaCO}{}_3$ decomposes to $\mathrm{CaO}$
3. C$\mathrm{Ca}(\mathrm{OH}){}_2$ is regenerated
4. Dsoluble $\mathrm{Ca}(\mathrm{HCO}{}_3){}_2$ is formed