Three Point Charges, Q₁ = 2 $\mu$ C, Q₂ = 2 $\mu$

Three point charges, q₁ = 2.0 $\mu$ C, q₂ = 2.0 $\mu$ C, and q₃ = -1.0 $\mu$ C,are located at the vertices of an equilateral triangle of side length 30 cm.What is the potential energy of this arrangement?

A) 0.24 J
B) 0.12 J
C) -0.24 J
D) -0.12 J
E) 0