Answer:
New force, F' = F
Step-by-step explanation:
Given that, two small balls, A and B, attract each other gravitationally with a force of magnitude F. It is given by :

If we now double both masses and the separation of the balls, the new force is given by :

F' = F
So, the new force remains the same as previous one. Hence, the correct option is (d) "F"