The Three Point Charges Shown in the Figure Form an Equilateral

The three point charges shown in the figure form an equilateral triangle with sides $4.9 \mathrm {~cm}$ long. What is the electric potential (relative to infinity) at the point indicated with the dot, which is equidistant from all three charges? Assume that the numbers in the figure are all accurate to two significant figures. $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 9.0 \times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 } \right)$

A) $1900 \mathrm {~V}$
B) $1300 \mathrm {~V}$
C) $640 \mathrm {~V}$
D) $0.00 \mathrm {~V}$