During thhe preparation of `H_(2)S_(2)O_(8)` (per disulphuric acid) `O_(2)` gas also releases at anode as byproduct. When 9.72 of `H_(2)` releases at cathode and `2.35`L `O_(2)` at anode at STP, the weight of `H_(2)S_(2)O_(8)` produced in gram is
A. 87.12
B. 43.56
C. 83.42
D. 51.74