Assertion : Zone refining is based on the solubility of impurities in the molten state than in the solid state of the metal. Reason : Pure metal oxide is obtained in zone refining.

• A

  If both assertion and reason are true and reason is the correct explanation of assertion.
• B

  If both assertion and reason are true but reason is not the correct explanation of assertion.
• Correct answer
  C

  If assertion is true but reason is false.
• D

  If both assertion and reason are false.

Hence, the correct answer is option: 'C'.