The correct answer is limestone. Limestone is a sedimentary rock composed mainly of calcium carbonate (CaCO3). It is the most common type of rock used in the production of cement. Limestone is quarried and then crushed into small pieces. These pieces are then heated in a kiln to remove the carbon dioxide, leaving behind calcium oxide (CaO). The calcium oxide is then mixed with clay and sand to form cement clinker. The clinker is then ground into a fine powder and mixed with water to form cement.
Bauxite is an ore of aluminum. It is not used in the production of cement.
Iron ore is an ore of iron. It is used in the production of iron and steel.
Manganese is a mineral that is used in a variety of applications, including the production of steel. It is not used in the production of cement.