The correct answer is: d) All of the above.
Limestone is a sedimentary rock composed mainly of calcium carbonate (CaCO3). It is a common rock type found in many parts of the world, including Arunachal Pradesh. Limestone is used in a variety of industries, including cement production, iron and steel production, and construction.
In cement production, limestone is calcined (heated to a high temperature) to produce lime. Lime is then mixed with clay and other materials to produce cement. Cement is a key ingredient in concrete, which is used in a variety of construction projects.
In iron and steel production, limestone is used to remove impurities from iron ore. Limestone is also used to produce flux, which is a substance that helps to remove impurities from molten iron.
In construction, limestone is used as a building material. Limestone is a strong and durable stone that can be used to construct a variety of structures, including buildings, bridges, and roads.
Limestone is an important resource that is used in a variety of industries. The limestone deposits in Arunachal Pradesh are a valuable resource that can be used to support economic development in the state.