During a chemical reaction, an iron atom became the ion fe2+. what happened to the iron atom?

            The Iron atom got oxidized.

                        In inorganic chemistry Oxidation and Reduction reactions are defined as,

Reduction:

                 The reaction in which an atom accepts electrons is known as reduction reaction.

Example:

                                      2 Na  +  Cl₂    →     2 NaCl

In this reaction Chlorine oxidation state has changed from 0 to -1. Hence, it has gained one electrons therefore, it is designated as being reduced.

Oxidation:

                 The reaction in which an atom looses electrons is known as reduction reaction.

Examples:

                                      2 Na  +  Cl₂    →     2 NaCl

In this reaction Sodium's oxidation state has changed from 0 to +1. Hence, it has lost one electrons therefore, it is designated as being Oxidized.

                                       2 Fe + 3 O₂    →     2 FeO

In this reaction Iron's oxidation state has changed from 0 to +2. Hence, it has lost two electrons therefore, it is designated as being Oxidized.

i think it's letter a.