By definition, the gravitational force is given by:

Where,
G: gravitational constant
m1: mass of object 1
m2: mass of object 2
r: distance between objects:
We know that the force is equal to 10N:

If the distance is double we have:


Therefore, the new force is:
2.5 newtons
Answer:
the changed force of attraction between them is:
A. 2.5 newtons