Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: Two identical books are on opposite ends of a table. Which of these would increase the gravitational force exerted between the two books?
decrease the distance between the books
None. The gravitational force between the two books is determined by their mass and the distance between them, not by their position on the table.