Statement $A$: Extraction of magnesium is done by the electrolysis of a molten mixture of $MgCl_2$,$NaCl$,and $CaCl_2$.
Reason $R$: Calcium chloride acts as a reducing agent.

• A
  Both Statement $A$ and Reason $R$ are true and Reason $R$ is the correct explanation of Statement $A$.
• B
  Both Statement $A$ and Reason $R$ are true,but Reason $R$ is not the correct explanation of Statement $A$.
• C
  Statement $A$ is true,but Reason $R$ is false.
• D
  Both Statement $A$ and Reason $R$ are false.