Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$
Assertion $(A):$ Aluminium is extracted from bauxite by the electrolysis of a molten mixture of $Al_2O_3$ with cryolite.
Reason $(R):$ The oxidation state of $Al$ in cryolite is $+3$.
In the light of the above statements,choose the most appropriate answer from the options given below:

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