The range of the real valued function $f(x)=\operatorname{Cos}^{-1}\left(\frac{3}{\sqrt{9 x^2-12 x+22}}\right)$ is

• A

  $\left(0, \frac{\pi}{4}\right]$
• Correct answer
  B

  $\left[\frac{\pi}{4}, \frac{\pi}{2}\right)$
• C

  $[0, \pi]$
• D

  $\left[\frac{\pi}{6}, \frac{\pi}{2}\right)$

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