Which of the following turns lime water milky?

Limewater is a diluted aqueous calcium hydroxide [$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$] solution. Additionally, it has a limited water solubility at ambient temperature. This molecule reacts with a certain gas to produce calcium carbonate, which precipitates as a turbid substance.

Limewater, a calcium hydroxide solution, combines with carbon dioxide gas to create a white precipitate of calcium carbonate. As previously mentioned, limewater is a calcium hydroxide solution. The limewater solution bubbles through carbon dioxide, which causes the limewater to turn milky or murky white. 
One of the main components of life on earth is carbon dioxide, sometimes referred to by its chemical name ${\mathrm{CO}}_2$. The reaction that occurs when it is added to lime water is as follows.
$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2 + {\mathrm{CO}}_2\to {\mathrm{CaCO}}_3$
The equilibrium shifts backward and the solution once more becomes colorless when an excess of the gas is passed through it.

Hence, the correct answer is option B.