Calculate the mass percent `(w//w)` of sulphuric acid in a solution prepared by dissovles 4 g of sulphur trixoide in a 100ml of sulphuric acid solution containing 80 mass percent `(w//w)` of `H_2SO_4` and having a density of 1.96 g/ml.
(Molecular weight of `H_2SO_4=98 gm`) Taken reaction `SO_3+H_2OtoH_2SO_4`
A. 0.8085
B. 0.84
C. 0.4165
D. None of these