Answer: The force between the charges is reduced to half.
Step-by-step explanation:
We know that
F = product of the charges/square of the distance between them
i.e. F = q1 q2 / r^2
If one charge is doubled and the distance is doubled then force can be written as
F' = 2q1q2/4r^2
F' = 1/2F
Therefore the force is reduced to half.