Aregion of space in which a measurable gravitational force is indicated by the force exerted on a test mass is called

Gravitational field

Explanation:

An object of mass M exerts a force (gravitational force) of attraction on any other object of mass m. The magnitude of this force is

where G is the gravitational constant and r the separation between the two objects.

Since the object of mass M exerts this force on any other object located around it, we can think as a "gravitational field", which is the region of space around the object of mass M that exerts a gravitational force on other object. This way, the force exerted on another object of mass m can be rewritten as

F = mg

where

is called strength of the gravitational field.

option number c is the right answer.