Answer:
The International Astronomical Union
Step-by-step explanation:
The International Astronomical Union or International Astronomical Union is a scientific society whose individual members are professional astronomers from various countries, holders of doctoral degrees or higher, who work in astronomy research and education.
Until the year 2006, the International Astronomical Union considered Pluto to be the ninth planet in the solar system, and although it was very close to the so-called Gaseous Giants (Jupiter, Saturn, Uranus and Neptune), it was the smallest of the planets in our system. However, after the discovery of the dwarf planet Eris and the (now held as false) perspective that it was larger than Pluto, scientists started wondering whether Pluto could actually be classified as a planet.
After a convention held in that year, the necessary criteria were established and re-evaluated to define what is a planet or not. Pluto did not pass one of them, which was: to have an orbit that is not directly influenced by other planets. Thus, Pluto was "demoted" to the dwarf planet classification.