The Plates of a Parallel Plate Capacitor Each Have an Area

Multiple Choice

The plates of a parallel plate capacitor each have an area of 0.40 m² and are separated by a distance of 0.02 m. They are charged until the potential difference between the plates is 3000 V. The charged capacitor is then isolated.
-Suppose that a dielectric sheet is inserted to completely fill the space between the plates and the potential difference between the plates drops to 1000 V. Determine the dielectric constant.

A) 0.333
B) 0.666
C) 3.0
D) 6.0
E) 2000