halving the distance between them doubling the distance between them halving the distance between them and doubling their mass doubling the distance between them and halving their mass
I gave my students this multiple choice question: Which of these will reduce the gravitational force between two objects the most?

Only one answer is correct among these 4 choices:
- halving the distance between them
- doubling the distance between them
- halving the distance between them and doubling their mass
- doubling the distance between them and halving their mass

Could you tell me which one is correct?

doubling the distance between them and halving their mass