A one litre flask contains some mercury. It is found that at different temperatures the volume of air inside the flask remains the same. The volume of mercury in the flask is `(alpha_(glass)=9xx10^(-6)//^(@)C,gamma_(Hg)=180xx10^(-6)//^(@)C)`
A. `150cm^(3)`
B. `225cm^(3)`
C. `300cm^(3)`
D. `450cm^(3)`