One Negative and Two Positive Charges, Each of Magnitude 3

Multiple Choice

One negative and two positive charges, each of magnitude 3 ìC, are at the vertices of an equilateral triangle of side 50.0 cm. What is the potential (relative to zero at infinity) at the mid-point between the two positive charges?

A) 1.3 × 10⁶ V
B) 1.5 × 10⁵ V
C) 1.2 × 10⁵ V
D) 7.5 × 10⁴ V