Four identical air-filled parallel-plate capacitors, labeled 1, 2, 3, and 4, each have initial capacitance \(C_0\) and plate separation \(d\). Each capacitor is initially connected to an identical battery of potential difference \(V_0\) until fully charged to an initial stored energy \(U_0\). The capacitors then undergo the following separate modifications:

Capacitor 1: Remains connected to the battery while its plate separation is increased to \(2d\).

Capacitor 2: Is disconnected from the battery, after which its plate separation is increased to \(2d\).

Capacitor 3: Remains connected to the battery while its plate separation is decreased to \(d/2\).

Capacitor 4: Is disconnected from the battery, after which its plate separation is decreased to \(d/2\).

Which of the following correctly ranks the final electric potential energies \(U_1\), \(U_2\), \(U_3\), and \(U_4\) stored in the four capacitors?