Two equal charges q are placed at a distance of 2a and a third charge -2q is placed at the midpoint. The potential energy of the system is ....
Options:
(a) `(9q^2)/(8πepsilon_o a)`
(b) `q^2/(8πepsilon_o a)`
(c) `-(7q^2)/(8πepsilon_o a)`
(d) `(6q^2)/(8πepsilon_o a)`