Which of the following statements is correct regarding the gravitational force?

The gravitational force is independent of &the intervening medium. In other words, the force between two masses remains the same whether they are in air, vacuum, water or separated by a brick wall'
Hence, (a) is an incorrect statement.
The gravitational force is a conservation force.
Hence, (b) is an incorrect statement.
The gravitational force obeys Newton's third law of motion. Thus, it form action-reaction pair.
Hence, (c) is a correct statement.
The gravitational force is a central force. Hence, (d) is an incorrect statement.