During the preparation of H2S2O8 (per disulphuric acid) O2 gas also releases at anode as byproduct. When 9.72 L of H2 releases at cathode and 2.35 L O2 at anode at STP, the weight of H2S2O8 produced in gram is
(a) 87.12
(b) 43.47
(c) 83.42
(d) 51.74