A thin, nonconducting semicircular arc of radius \(R\) is fixed in the \(xy\)-plane and centered at the origin. The arc extends from \(\theta = -\dfrac{\pi}{2}\) to \(\theta = \dfrac{\pi}{2}\), where \(\theta\) is measured counterclockwise from the positive \(x\)-axis. The linear charge density along the arc varies according to \(\lambda(\theta) = \lambda_0 \cos\theta\), where \(\lambda_0\) is a positive constant. Assuming the electric potential is zero at infinity, which of the following expressions correctly represents the integral setup to determine the electric potential \(V\) at the origin?