The correct answer to the question is D). Gravity.
Step-by-step explanation:
Before coming into any conclusion, first we have to understand centripetal force.
Centripetal force is the force which is required to keep a body moving in a circular path. This force always acts along the radius and towards the centre.
As per the question, the object is moving around the earth. As it is moving in a orbit, it needs a centripetal force which will help the object stick to the orbit.
The centripetal force required is provided to the object by the gravitational force of earth .
Air resistance and friction play no role in imparting centripetal force to the object.
Hence, the correct option of this question is gravity, which is the only force that acts on an object orbiting earth.