Answer:
Increasing the masses of the objects and decreasing the distance between the objects.
Step-by-step explanation:
Gravitational force always act between two objects that have mass. The gravitational force is a weak force and attractive in nature.
The force of pull depends on the masses of the two objects and the distance between them.
The formula to calculate gravitational force between two objects having masses 'm' and 'M' and separated by a distance 'd' is given as:
Where, 'G' is called the universal gravitational constant.
Now, from the above formula, it is clear that, the force of gravitation is inversely proportional to the square of the distance between the two objects and directly proportional to the masses of the two objects.
This means that, if masses increase with other parameters constant, force will increase and vice-versa. If distance decreases with other parameters constant, force will increase and vice-versa.
So, on combining the above two relations,we are certain that if one increases the masses and decrease the distance between, the gravitational force will definitely increase.
So, the third option is correct.