decrease the distance between the books decrease the mass of the books decrease the mass of the table decrease the temperature in the room
I gave my students this multiple choice question: Two identical books are on opposite ends of a table. Which of these would increase the gravitational force exerted between the two books?

Only one answer is correct among these 4 choices:
- decrease the distance between the books
- decrease the mass of the books
- decrease the mass of the table
- decrease the temperature in the room

Could you tell me which one is correct?

decrease the distance between the books