If $Z=r(\cos \theta+i \sin \theta),(\theta \neq-\pi / 2)$ is a solution of $x^3=i$, then $r^9(\cos \theta+i \sin \theta)^9=$

• A

  $\frac{\sqrt{3}}{2}+\frac{1}{2} i$
• B

  1
• Correct answer
  C

  -i
• D

  $\frac{-\sqrt{3}}{2}+\frac{1}{2} i$

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