Electrostatic force and gravitational force differ in which respect?
A) Conservative force
B) Central force
C) Principle of superposition.
D) Dependence on the intervening medium

Hint: We know that, electrostatic force is the force between the two charges which are placed at a distance and the opposite charges exert an attractive electrostatic force and similar charges exert repulsive force. Gravitational force is the force which attracts any two objects with masses and it always pulls the masses together.

Complete answer:
Let us take the all the options one by one and analyzing them to get a correct option,
Option A: conservative forces are the forces in which the work done is independent of the path. So, we can see that in electrostatic force the work done on a charge is independent of the path taken and for gravitational force, we know that the work done on moving an object by gravitational force is independent of path. So, both the forces are conservative.
Hence, this option is incorrect.

Option B: Central forces are the forces in which the magnitude of the force is proportional to the distance between two objects. So, gravitational force and electrostatic force are central forces.
Hence, this option is also incorrect.

Option C: Principle of superposition states that the resultant of all the forces or the charges is equal to the sum of all the individual forces and charges. Hence, both the gravitational and electrostatic force follows the principle of superposition.
Hence, this option is also incorrect.

Option D: we know that the gravitational force is not dependent on medium and electrostatic force is dependent on medium. The medium decides the absolute permittivity of space which in turns decides the electric field. Hence, these forces are different in this respect.
Hence, this is the correct option.

Hence, the correct option is D.

Note: We have studied the gravitational and electrostatic force in detail and we got to know that these forces are the same in many respects. But we get to know that gravitational force is independent of the medium whether electrostatic force is dependent on the medium.