The correct answer is: C. Mica
Kabutra and Nakia hill regions are famous for mica in Bihar. Mica is a mineral that is used in a variety of products, including electronics, cosmetics, and roofing. It is a lightweight, transparent mineral that is often used as a filler or insulator.
Gold is a precious metal that is used in jewelry and other decorative items. It is also used in electronics and other industries. Pyrite is a mineral that is often mistaken for gold. It is a yellow mineral that is sometimes called “fool’s gold.” Saltpetre is a mineral that is used in gunpowder and other explosives. It is also used in fertilizers and other products.
Mica is a more common mineral than gold, pyrite, or saltpetre. It is also a more versatile mineral, as it can be used in a variety of products. Therefore, Kabutra and Nakia hill regions are famous for mica in Bihar.