The argument that best supports Barbie's claim that the gravitational force is greater between the objects in Figure A is:
The distance between the objects in Figure A is less than the distance between the objects in Figure B.
Gravitational force is governed by Newton's law of universal gravitation, which states that the force of gravity between two objects increases with greater mass and decreases with greater distance. Therefore, if the distance between the objects in Figure A is less than the distance between the objects in Figure B, the gravitational attraction would indeed be greater in Figure A, assuming the masses are comparable.