A point charge \(+Q\) is fixed at the origin. A physical electric dipole aligned along the \(x\)-axis consists of charge \(-q\) at \(x = r\) and charge \(+q\) at \(x = r + s\), where \(s\) is a fixed positive separation distance and \(r > 0\). The electrostatic potential energy of the dipole due to the charge \(+Q\) is given by \(U(r) = kQq\left(\dfrac{1}{r + s} - \dfrac{1}{r}\right)\). In the limit where the distance to the dipole is much greater than its size (\(r \gg s\)), which of the following correctly gives the leading-order expression for \(U(r)\) including its first non-vanishing correction term in terms of the dipole moment \(p = qs\), and correctly compares \(U(r)\) to the ideal point-dipole potential energy \(U_{\text{ideal}} = -\dfrac{kQp}{r^2}\)?