Assertion: The number of tetrahedral voids is double the number of octahedral voids. Reason: The size of the tetrahedral voids is half of that of the octahedral void.

• 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'.