In the manufacturing of metallic sodium by fused salt-electrolysis method (Down's process), small amount of ${\mathrm{CaCl}}_2$ that added is known as auxiliary electrolyte and is used to :

A little amount of calcium chloride is added to the Down's method, which uses fused salt electrolysis to create metallic sodium, to lower the melt temperature. The melt temperature is reduced by calcium chloride from 1075K to 850K.

Hence the option A and B are correct.