Question on Chemical Kinetics

Decomposition of \(H_2O_2\) follows a first order reaction. In fifty minutes the concentration of \(H_2O_2\) decreases from 0.5 to 0.125 M in one such decomposition. When the concentration of \(H_2O_2\_ reaches 0.05 M, the rate of formation of \(O_2\) will be 

A) \(6.93 \times 10^{-4} \ mol min^{-1}\)

B) \(2.66\ L \ min^{-1} \ at \ STP\)

C) \(1.34 \times 10^{-2} \ mol min^{-1}\)

D) \(6.93 \times 10^{-2} \ mol min^{-1}\)