When A $6.00 - \mu \mathrm { F }$ Air-Filled Capacitor Has a Charge Of

When a $6.00 - \mu \mathrm { F }$ air-filled capacitor has a charge of $\pm 40.0 \mu \mathrm { C }$ on its plates, how much potential energy is stored in this capacitor?

A) $103 \mu \mathrm { J }$
B) $133 \mu \mathrm { J }$
C) $113 \mu \mathrm { J }$
D) $123 \mu \mathrm { J }$
E) $143 \mu \mathrm { J }$