The Concentration of an Old Solution of Hydrogen Peroxide Is $\rarr$

The concentration of an old solution of hydrogen peroxide is being tested because hydrogen peroxide decomposes over time. The following reaction is catalyzed by potassium iodide and used to determine the concentration. If 3.0 ml of the peroxide solution is tested and produces 55 ml of O_2(g) at 750 mm Hg and 23°C, how many grams of hydrogen peroxide were in the solution?
2 H₂O_2(aq) $\rarr$ 2 H₂O_(l) + O_2(g)

A) 0.0245 g
B) 0.12 g
C) 0.60 g
D) 12.4 g
E) 0.15 g