1.34g of hydrated sodium tetraoxosulphate(vi) was heated to give an hydrous salt weighting 0.71g,the formular of the hydrated salt is;a)Na2So4 7H2O b)Na2SO4 3H2O c)NaSo4 2H2O d)Na2So4 1H2O

b) Na2SO4 3H2O