Correct Answer - Option 4 : 45%
Explanation:
Limestone: It is a sedimentary rock composed primarily of calcite, a calcium carbonate mineral with a chemical composition of CaCO3.
Dolomite: It is a mineral composed of calcium and magnesium carbonate combined in equal molecular property, expressed by the formula CaMg(CO3)2.
Dolomite contains a 45% carbonate of magnesia.