A uniform rod of mass \(M\) and length \(L\) is pivoted about a horizontal frictionless axle that passes through the rod at a point located a distance \(L/6\) from one of its ends. The rod is held in a horizontal position, as shown in the figure, and then released from rest. The rotational inertia of a uniform rod about its center of mass is \(\dfrac{1}{12} ML^2\). Which of the following is a correct expression for the magnitude of the initial angular acceleration of the rod?