Point Charges of Equal Magnitudes (25 NC) and Opposite Signs

Point charges of equal magnitudes (25 nC) and opposite signs are placed on (diagonally) opposite corners of a 60-cm × 80-cm rectangle. If point A is the corner of this rectangle nearest the positive charge and point B is located at the intersection of the diagonals of the rectangle, determine the potential difference, V_B − V_A.

A) −47 V
B) +94 V
C) zero
D) −94 V
E) +47 V