Two Point Charges Are Held at the Corners of a Rectangle

Multiple Choice

Two point charges are held at the corners of a rectangle as shown in the figure. The lengths of sides of the rectangle are 0.050 m and 0.150 m. Assume that the electric potential is defined to be zero at infinity.
-What is the potential difference, V_B - V_A, between corners A and B?

A) -8.4 × 10⁵ V
B) -7.8 × 10⁵ V
C) -7.2 × 10⁵ V
D) -6.0 × 10⁵ V
E) zero volts