Four Point Charges of Magnitude $6.00 \mu \mathrm { C }$

Multiple Choice

Four point charges of magnitude $6.00 \mu \mathrm { C }$ and are at the corners of a square $2.00 \mathrm {~m}$ on each side. Two of the charges are positive, and two are negative. What is the electric potential at the center of this square, relative to infinity, due to these charges? $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 8.99 \times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 } \right)$

A) $153 \mathrm { kV }$
B) $306 \mathrm { kV }$
C) $76.4 \mathrm { kV }$
D) $0 \mathrm {~V}$
E) $61.0 \mathrm { kV }$