The correct answer is: A. Borax.
Borax is a mineral that is found in the Puga valley in Leh district. It is a white, powdery substance that is used in a variety of products, including detergents, cosmetics, and glass. Borax is also used to make boric acid, which is a common household cleaner.
Limestone is a sedimentary rock that is made up of calcium carbonate. It is a common building material and is also used in the production of cement. Uranium is a radioactive metal that is used in nuclear power plants. Iron ore is a mineral that is used to make iron and steel.
Borax is the only mineral that is found in the Puga valley in Leh district. The other minerals are not found in this area.