The Electrostatic Potential Energy of the System of Point Charges

The electrostatic potential energy of the system of point charges q₁ = 1 μC, q₂ = -2 μC, and q₃ = 3 μC at the corners of the equilateral triangle whose side s = 40 cm is

A) 1.10 J.
B) 0.990 J..
C) -0.631 J.
D) 0.330 J.
E) -0.113 J.