The correct answer is A. Gravitational force.
Gravitational force is a force of attraction between any two objects with mass. The more mass an object has, the stronger its gravitational pull. The Earth has a very strong gravitational pull, which is why objects on Earth fall down when they are dropped.
Satellites are objects that are put into orbit around the Earth. They are held in orbit by the Earth’s gravitational pull. The Earth’s gravity pulls on the satellite, but the satellite is moving so fast that it keeps falling around the Earth instead of falling into it.
Centripetal force is a force that acts towards the center of a circle. It is what keeps objects moving in a circle. Centrifugal force is a force that acts away from the center of a circle. It is what makes objects feel like they are being pushed out of a circle.
Neither centrifugal force nor centripetal force are responsible for keeping satellites in orbit. Satellites are in orbit because of the Earth’s gravitational pull.