Pure sodium chloride is obtained by :

Pure sodium chloride is obtained by crude salt is dissolved in minimum amount of water and filtered to remove insoluble impurities. The solution is then saturated with $\mathrm{HCl}$ gas.

Pure sodium chlorides are made by dissolving crude sodium chloride because they are quick to absorb moisture from the air. <br> By combining crude sodium chloride with the least quantity of water possible and filtering the solution to eliminate insoluble contaminants, pure sodium chlorides can be produced. <br> $\mathrm{HCl}$ gas has been absorbed completely by this solution.

Hence, option B is correct.