Answer- The correct choice of answer out of all would be option C.
Step-by-step explanation
The given substance magnesium chloride made out of combination of chlorine and magnesium is a compound. Where magnesium has two positive ions and chlorine has two negative ions which trigger the reaction.
Hence the oxidation of the 2 positive ions of Magnesium takes place and reduction of the Negative Ion chlorine has to offer attract and stabilize each other by forming the compound .