Answer & explanation
Correct answer: option 3
Potential Energy of the system $ U = 2 \times \frac{k.q.-2q}{4\pi\epsilon_0 a} + \frac{k.q.q}{4\pi\epsilon_0 2a} = \frac{-7kq^2}{8\pi\epsilon_0 a}$
Correct answer: option 3
Potential Energy of the system $ U = 2 \times \frac{k.q.-2q}{4\pi\epsilon_0 a} + \frac{k.q.q}{4\pi\epsilon_0 2a} = \frac{-7kq^2}{8\pi\epsilon_0 a}$