If $O(0,0,0), A(1,2,1), B(2,1,3)$ and $C(-1,1,2)$ are the vertices of a tetrahedron, then the acute angle between its face $O A B$ and edge $B C$ is

• A

  $\operatorname{Cos}^{-1}\left(\frac{6 \sqrt{2}}{5 \sqrt{7}}\right)$
• Correct answer
  B

  $\operatorname{Sin}^{-1}\left(\frac{6 \sqrt{2}}{5 \sqrt{7}}\right)$
• C

  $\operatorname{Tan}^{-1}\left(\frac{6 \sqrt{2}}{5 \sqrt{7}}\right)$
• D

  $\frac{\pi}{2}$

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