Which two, or more, of the following actions would increase the energy stored in a parallel plate capacitor when a constant potential difference is applied across the plates?
1. increase the area of the plates
2. decrease the area of the plates
3. increase the separation between the plates
4. decrease the separation between the plates
5. insert a dielectric between the plates

choices
a) 2,4
b) 1.3
c) 1,4, 5
d) 2, 3, 5