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 = 30 cm is

A) 1.1 J.
B) 0.99 J.
C) 0.63 J.
D) 0.33 J.
E) 0.11 J.