Which objects will likely have the smallest gravitational force between them?

Explanation:

the objects having very small masses and greater distance between themyou will understand better using  the newtons law of gravitation

which states that

                     F=m₁m₂/r²

this clearly shows that smaller are the masses smaller would be the force of gravitation and vice versa

c. rb

explanation:

the atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding shells of electrons.

i think the answer is a, hope this is right, that would be my best guess.