Answer:
D.) One atom of Sulfur
Explanation:
An atom of sulphur has the oxidation of -2 equivalent to Mg +2. These atoms can easily react in a 1 : 1 mole ratio, to form magnesium sulphide, MgS,
The reaction equation:
[tex]Mg^{2+} + S^{2-}[/tex]→ [tex]MgS[/tex]