Concept:The International Astronomical Union (IAU) set three criteria for a planet in 2006. Pluto meets only two of them.Explanation:A planet must orbit the Sun, be spherical, and clear its orbit of debris. Pluto orbits the Sun and is round. However, its orbit crosses Neptune’s and shares space with many Kuiper Belt objects. Since it has not cleared its orbit, Pluto is now classified as a dwarf planet. The main reason is that it is not large enough to dominate its orbital zone.Answer:B. Because it is not large enough to be considered as a planet