C-06-Q157mediumsingle_mcqThe formula of blue vitriol is—aCuSO4\mathrm{CuSO_4}CuSO4bCuSO4⋅5H2O\mathrm{CuSO_4 \cdot 5H_2O}CuSO4⋅5H2OcCuSdCu(OH)2\mathrm{Cu(OH)_2}Cu(OH)2