Decomposition of H2O2 follows a first order reaction. In 50 min, the concentration of H2O2 decreases from 0.5 to 0.125 M in one such decomposition. When the concentration of H2O2 reaches 0.05 M, the rate of formation of O2 will be
(a) 6.93 x10-4 mol min-1 (b) 2.66 L min-1 at STP
(c) 1.34 x10-2 mol min-1 (d) 693 x10-2 mol min-1