The correct option is
B sodium tetraborate decahydrate
Answer:- (C) Sodium tetraborate decahydrate
Borax, also known as sodium perborate is an important boron compound, a mineral, and the salt of boric acid. It is usually a white powder consisting of soft colorless crystals that dissolve easily in water.
Chemical formula of borax is -
Na2B4O7.10H2O and called as sodium tetraborate decahydrate.