We know that according to the law of gravitation, the gravitational force between any two bodies that have some mass is given as:

${\text{F}}_{ }=\text{G}.\frac{{\text{Mm}}_{ }}{R_{ }^2}$
Where M and m are the masses of the two bodies, R is the distance between them and G is the universal gravitation constant.

In the given question, 

$\text{R}=2\text{R}$

Substituting the value,

$\text{F}=\frac{\text{GMm}}{{\left(\text{2R}\right)}^{\text{2}}}$

$\text{F}=\frac{\text{GMm}}{{\text{4R}}^{\text{2}}}$

Force will reduce to a quarter.

Therefore, option D is the correct answer.