A parallel-plate capacitor with distance of separation between the plates, d, is charged and then disconnected from the battery. The plates are then pushed together to decrease their separation to (1/2)d. Which of the following statements is true? O The energy stored in the capacitor is four times the original level. O The energy stored in the capacitor is one quarter times the original level. O The energy stored in the capacitor is not changed. O The energy stored in the capacitor is half the original level. O The energy stored in the capacitor is twice the original level.