Four Identical Point Charges (+6

Four identical point charges (+6.0 nC) are placed at the corners of a rectangle which measures 6.0 m * 8.0 m.If the electric potential is taken to be zero at infinity,what is the potential at the geometric center of this rectangle?

A) 58 V
B) 63 V
C) 43 V
D) 84 V
E) 11 V