Which one of the following statements is correct?

• A

  $\sin ^2 30^{\circ}, \sin ^2 45^{\circ}, \sin ^2 60^{\circ}$ are in GP
• B

  $\cos ^2 30^{\circ}, \cos ^2 45^{\circ}, \cos ^2 60^{\circ}$ are in GP
• C

  $\cot ^2 30^{\circ}, \cot ^2 45^{\circ}, \cot ^2 60^{\circ}$ are in AP
• Correct answer
  D

  $\tan ^2 30^{\circ}, \tan ^2 45^{\circ}, \tan ^2 60^{\circ}$ are in GP

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