A uniform rod of length l and mass m is free to rotate in a vertical plane about A. The rod initially in horizontal position is released. The initial angular acceleration of the rod is (Moment of inertia of rod about A is $\frac{ ml^2}{3}$ ):

Question

( A ) $\frac{3g}{2l}$
( B ) $\frac{2l}{3g}$
( C ) $mg\frac l 2$
( D ) $\frac{3g}{2l^2}$