If $\frac{1}{2} \operatorname{Sin}^{-1}\left(\frac{3 \sin 2 \theta}{5+4 \cos 2 \theta}\right)=\operatorname{Tan}^{-1} x$ then $x=$

• A

  $\tan \frac{\theta}{3}$
• Correct answer
  B

  $\frac{1}{3} \tan \theta$
• C

  $\tan 3 \theta$
• D

  $\frac{1}{3} \tan 3 \theta$

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