Uniform \( \operatorname{rod} A B \) is hinged at end \( A \) in ho...

Uniform \( \operatorname{rod} A B \) is hinged at end \( A \) in horizontal position as shown in the figure. The other end is connected to a block through a massless string as shown. The pulley is smooth and massless. Mass of block and rod is same and is equal to \( m \). Then, acceleration of block just after release from this position is
(a) \( 6 g / 13 \)
(b) \( g / 4 \)
(c) \( 3 g / 8 \)
(d) None of these