A parallel-plate capacitor having circular plates of radius R and separation d is charged to a potential difference by a battery. It is then removed from the battery. If the plates are moved closer together (there may be more than one correct choice), A. the amount of charge on each of them will increase
B. the amount of charge on each of them will decrease
C. the amount of charge on each of them will stay the same
D. the energy stored in the capacitor increases