All of the planets in Earth's solar system must follow the same plane of motion. What's this plane called?

A. Plane of the ecliptic

B. Plane of spherical motion

C. Plane of orbital rotation

D. Plane of triangulation

Answer A. Plane of the ecliptic

A. Plane of the ecliptic

Explanation:

The plane of ecliptic refers to the plane in which all the planets and the Sun move across in the sky as observed from the Earth. Ecliptic is the path of the Sun's motion in the sky as observed from the Earth throughout the year. The planets must also follow the same plane of motion as they lie in the same plane as that of the Sun.

C. Plane of orbital rotation

Explanation:

The orbital plane of an object orbiting around another is the geometric plane that contains the orbit in question.

By definition, the inclination of a planet in the solar system is the angle between the orbital plane of the solar system and the orbital plane of the Earth.