A simple pendulum of length \(L\) is released from rest at a small angle \(\theta_0\). A thin horizontal peg is located at a distance \(d\) directly below the pivot point, where \(d < L\). As the bob swings through its lowest point, the string strikes the peg, causing the bob to swing the remainder of its arc with a shorter effective length. Which of the following is a correct expression for the total time required for the bob to complete one full oscillation?