The correct answer is: a) Barytes.
Andhra Pradesh is a leading producer of barytes in India. Barytes is a heavy, white mineral that is used in a variety of industrial applications, including the production of oil and gas, paints, and ceramics.
Coal is a fossil fuel that is used to generate electricity and power industrial processes. Iron ore is a mineral that is used to produce iron and steel. Copper is a metal that is used in a variety of applications, including electrical wiring, plumbing, and construction.
Barytes is a more important mineral than coal, iron ore, or copper in Andhra Pradesh. It is used in a variety of industrial applications, and it is a major source of revenue for the state.