The correct answer is: Iron Ore.
Gujarat is one of the largest producers of iron ore in India. The state has significant reserves of iron ore, which are located in the Kutch, Saurashtra, and Surat districts. The iron ore in Gujarat is of high quality and is used in the production of steel.
Lignite is a type of coal that is found in Gujarat. It is a low-grade coal that is used in the production of electricity.
Bauxite is a mineral that is used in the production of aluminum. There are small deposits of bauxite in Gujarat, but the state is not a major producer of this mineral.
Copper is a mineral that is used in the production of electrical wires and other products. There are small deposits of copper in Gujarat, but the state is not a major producer of this mineral.