Three 10 $\mu$ C Charges Are Placed Along the X-Axis,one Charge at X

Three 1.0 $\mu$ C charges are placed along the x-axis,one charge at x = -10 cm, another at the origin,and the last one at x = 10 cm.What is the total potential energy of this arrangement?

A) 0.27 J
B) -0.27 J
C) 0.72 J
D) 0.23 J
E) infinite (or indeterminate)