Select the word from the list that best fits the definition the light that a star actually gives off

Found a similar question on the Internet. Their answer is - The light that a star actually gives off is the apparent magnitude. Upon further research, apparent magnitude term is used by astronomers to describe how bright a star is or any celestial object as seen by an observer on Earth. There's also what they call as absolute magnitude. It represents how bright a star would look like if it were 10 parsecs or 3.26 light years away from the Earth.

4should be the last one n=4