Nagaland has significant reserves of:

The correct answer is: a) Iron ore

Nagaland has significant reserves of iron ore. The state is estimated to have about 200 million tonnes of iron ore reserves. The iron ore is of high quality and is suitable for use in the steel industry. The state government has been promoting the development of the iron ore industry in the state. Several companies have been granted mining leases in the state and are in the process of developing iron ore mines. The development of the iron ore industry is expected to boost the economy of the state and create employment opportunities for the people of the state.

The other options are incorrect because:

• Limestone is a sedimentary rock composed mainly of calcium carbonate. It is used in the construction industry, in the manufacture of cement, and in the production of lime. Nagaland does have some limestone reserves, but they are not significant.
• Coal is a fossil fuel formed from the remains of ancient plants. It is used in the generation of electricity, in the production of steel, and in the manufacture of chemicals. Nagaland does have some coal reserves, but they are not significant.
• Bauxite is an aluminum ore. It is used in the production of aluminum. Nagaland does not have any bauxite reserves.