Energy in Capacitors: an Ideal Air-Filled Parallel-Plate Capacitor Has Round

Multiple Choice

Energy in capacitors: An ideal air-filled parallel-plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its plates. All the geometric parameters of the capacitor (plate diameter and plate separation) are now DOUBLED. If the original capacitance was C₀, what is the new capacitance?

A) 4C₀
B) 2C₀
C) C₀
D) C₀/2
E) C₀/4