44.8% oxygen, 21.5% silicon, and 22.8% magnesium. There's also iron, aluminum, calcium, sodium, and potassium. These elements are all bound together in the form of silicate rocks, all of which take the form of oxides.
Answer is A. The reason to create such is to conduct electricity, and metal conducts electricity.
Hope this helps, Tiara
The molar mass of Fe would be 55.8450.