A rod of length L and mass M fixed at the origin at one end is placed along the x-axis at t = 0. It starts rotating about the z-axis in the x-y plane anti-clockwise as seen from the positive z-axis due to a force F always perpendicular to the rod acting at the free end. The angular acceleration of the rod is
1
\(\frac {F }{ML } \)
2
\(\frac {2F }{ML } \)
3
\(\frac {3F }{ML } \)
4
\(\frac {4F }{ML } \)