An atomic scientist was studying an atom and through experimentation found that the total negative charge of the area surrounding the nucleus is -9. Which statement correctly describes this atom?

This atom has nine clouds.
This atom has nine electrons.
This atom has nine neutrons.
This atom has nine protons.

The ANSWER is "This atom has nine electrons." (B)
I tried googling it and didn't find it, so I'm making this to help the other people on this question! :)
(Edgenunity 2020)