The correct answer is: a) Copper
Copper is a mineral that is found in the earth’s crust. It is a reddish-brown metal that is used in a variety of products, including electrical wiring, plumbing, and coins. Copper is mined in a number of countries around the world, including Sikkim.
Limestone is a sedimentary rock that is composed of calcium carbonate. It is a white or gray rock that is used in a variety of products, including cement, building materials, and fertilizer. Limestone is mined in a number of countries around the world, including Sikkim.
Iron ore is a mineral that is used to make iron. It is a black or brown rock that is found in the earth’s crust. Iron ore is mined in a number of countries around the world, including Sikkim.
Gold is a mineral that is found in the earth’s crust. It is a yellow metal that is used in a variety of products, including jewelry, coins, and electronics. Gold is mined in a number of countries around the world, including Sikkim.
Copper is the only mineral that is commercially mined in Sikkim. The other minerals are not mined commercially in Sikkim.