The sodium is made by electrolysis of a molten mixture of 40% NaCl and 60% CaCl₂ because 

• A

  CaCl₂ helps in the conduction of electricity

• B

  Ca²⁺ can reduce NaCl to Na

• C

  Ca²⁺ can displace Na from NaCl

• D

  this mixture has a lower melting point than NaCl