A thin, non-uniform rod of length \(L\) and total mass \(M\) lies along the \(x\)-axis between \(x = 0\) and \(x = L\). The linear mass density of the rod varies with position according to \(\lambda(x) = \dfrac{2M}{L^2}x\). A point particle of mass \(m\) is fixed on the \(x\)-axis at position \(x = -d\), where \(d > 0\). Which of the following expressions correctly represents the magnitude of the gravitational force exerted by the rod on the point particle?