Plant mass doubled Part A

Problem

Two identical planets pull on each other with a gravitational force $F$ described by this function:

$F=\frac{G{m}_1{m}_2}{r^2}$

where $m$ is the mass of a planet, $r$ is the distance between the centers of the planets, and G is a constant.

What is the new gravitational force if the distance between the planets is doubled?

The force is one$-$eighth the original force

The force is one$-$fourth the original force

The force is one$-$half the original force

The force is the same as the original force

The force is twice the original force

The force is four times the original force

The force is eight times the original force