An electron in a hydrogen-like ion with ground-state energy \(-E_0\) is initially in the ground state (\(n = 1\)). The energy of the \(n\text{th}\) bound state is given by \(E_n = -\dfrac{E_0}{n^2}\), as illustrated in the energy-level diagram. Which of the following expressions represents the minimum photon energy required to excite the electron from the ground state to the second excited state?