Question

the force between two charges at infinite separation is 1, zero,maximum, infinity​

Answer 1

Explanation:

Let q1 and q2be any two charges

Workdone in bringing any one of the two charges q1or q2from infinity to the given point against the electric force exerted by the other charge.

So, the very definition of potential energy is your question(i.e.) The workdone to separate the charges to infinity is the negative of the potential energy of the system of charges.