Question

2. An ion is a charged particle that is formed when

Answer 1

An ion is a charged particle that is formed when an atom gains electrons or an atom loses electrons.

First you need to know the definition of ion. An ion is a molecule or atom that has a positive or negative electrical charge. That is, an ion is an atom whose electric charge is not neutral. This charged particle can be positive or negative.  

Ionization is the chemical or physical process by which ions are produced. In this process, negatively charged ions are produced by gaining electrons and are known as anions. The positively charged are produced by the loss of electrons and are known as cations.

In summary, an ion is a charged particle that is formed when  an atom gains electrons or an atom loses electrons, and they are known as cations and anions respectively. The correct answer is both A and B.