The correct answer is: d) All of the above.
Limestone is a sedimentary rock composed mainly of calcium carbonate (CaCO3). It is the most common sedimentary rock in the world, and it is used in a variety of industries.
In the construction industry, limestone is used as a building material. It is used to make concrete, bricks, and other building products. Limestone is also used as a decorative stone.
In the cement production industry, limestone is used as a raw material. It is heated with clay and other materials to produce cement. Cement is a key ingredient in concrete.
In the steel industry, limestone is used to remove impurities from iron ore. It is also used to make flux, which is a substance that helps to remove impurities from molten steel.
Limestone is a valuable resource that is used in a variety of industries. It is a sustainable resource that can be recycled and reused.