The correct answer is (c) Limestone.
Limestone is a sedimentary rock composed mainly of calcium carbonate (CaCO3). It is the most common type of rock found in the Earth’s crust and is used in a variety of industries, including cement, steel, and paper.
Cement is a binding agent that is used to hold together aggregates (sand, gravel, and crushed stone) to form concrete. Limestone is one of the main ingredients in cement, along with clay, sand, and iron ore.
The cement industry in Tamil Nadu is one of the largest in India. The state has abundant reserves of limestone, which is a major factor in the growth of the industry. In 2018, the cement industry in Tamil Nadu produced over 30 million tonnes of cement, making it the second largest producer in India.
The other options are incorrect because they are not used in the production of cement. Iron ore is used in the production of steel, gypsum is used in the production of plasterboard, and bauxite is used in the production of aluminum.