The correct answer is C. Decreasing the distance between the objects
Step-by-step explanation:
Gravitational force and distance between the objects involved are inversely proportional variables; this means gravitation increases when the distance decreases. An example of this is that the Sun's gravitational force strongly attracts objects near it including planets in our Solar system, which causes planets to orbit the Sun. However, the force the Sun exerts on planets in other solar systems or in other galaxies is low due to the distance between this and the sun. In this context, to increase the gravitational force the distance between the objects should be decreased.