An anion is an atom that has

Agained one or more electrons.
Blost one or more electrons.
Cgained one or more protons.

Verified Answer :

An anion is an atom that has A. Gained one or more electrons.

I think the correct answer from the choices listed above is option A. An anion is an atom that has gained one or more electrons making it more negative since electrons are negatively charged and adding them to a neutral atom will make the atom negative.