Answer:
a. satellite.
Explanation:
In a general sense, the satellite is defined as anything that revolves around something else. They can be natural or artificial. In astronomy, the natural satellite can be defined as a smaller body that moves or revolves around a larger body, this body that is smaller is kept in orbit by gravitation. For example, the moon is considered a satellite because it orbits the earth. When talking about artificial satellites it is understood that they are objects built by people, where these devices orbit the earth and other planets of the solar system.
