A rigid body is rotating with a constant angular speed of $3 \mathrm{rad} . \mathrm{s}^{-1}$ about a fixed axis passing through the points $A$ and $B$ with coordinates $(0,-1,1)$ and $(1,1,3)$ respectively. Assuming all quantities in S.I. units, the instantaneous speed of the point P of the body with coordinates $(4,6,7)$ is

• Correct answer
  A

  $3$
• B

  $2$
• C

  $6$
• D

  $4$

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