During the Decomposition of CaCO₃(s) into CaO(s) and O₂(g), 100

During the decomposition of CaCO₃(s) into CaO(s) and O₂(g) , 100.0 mL of gas is collected by the displacement of water in a flask at 25°C with an atmospheric pressure of 755 mm Hg. The vapor pressure of water at this temperature is 23.8 mm Hg. What mass of oxygen was collected?

A) 0.679 mg
B) 21.7 mg
C) 12.9 mg
D) 0.807 mg
E) 126 mg