A uniform 9 kg rod with length 42 m has a frictionless pivot at one end. The rod is released from rest at an angle of 22 degrees beneath the horizontal. What is the angular acceleration of the rod immediately after it is released? Choose the correct option:
a) 0.25 rad/s²
b) 0.50 rad/s²
c) 0.75 rad/s²
d) 1.00 rad/s²