In a lead storag battery, Pb (anode) and `PbO_(2)` (cathode) are used. Concentrated `H_(2)SO_(4)` is used as electrolyte. The battery holds 3.5 litre acid with it . In the discharge process, the density of acid fell from 1.294 to 1.139 g/mL. The sulphuric acid of density `1.294" g mL"^(-1)` is 39 % by mass and that of density 1.139 g/mL is 20% by mass.
The amount of charge which the battery must have been used is :
A. 9.88 F
B. 8.98 F
C. 8.89 F
D. 7.88 F