Pluto has a shape that is nearly round, and it orbits the Sun. It has five known moons. Why is it called a dwarf planet and not a planet?

A.

It is too far from the Sun.

B.

Its orbit is not cleared of like-sized or larger objects.

C.

It is not large enough in size.

D.

It does not have rings.

B. Its orbit is not cleared of like-sized or larger objects

Explanation:

It has not cleared the neighborhood around its orbit, Pluto is considered a dwarf planet. It orbits in a disc-like zone beyond the orbit of Neptune called the Kuiper belt, a distant region populated with frozen bodies left over from the solar system's formation.

B). Its orbit is not cleared of like-sized or larger objects.

Explanation:

As per the question, the key reason for considering Pluto as a dwarf planet instead of a planet is that 'its orbit is not cleared of like-sized or larger objects.' Pluto was official declared a dwarf planet in the August 2006 by International Astronomical Union as it failed to prove itself as a governing gravitational object in its orbit and thus, could not clear the neighborhood surrounded by its orbit. Therefore, option B is the correct answer.