In an isothermal reversible expansion, if the volume of 96 gm of oxygen at 27°C is increased from 70 litres to 140 litres, then the work done by the gas will be

• A.            \[300\,R{{\log }_{10}}2\] 
• B.            \[81\,R{{\log }_{e}}2\]
• C.            \[900\,R{{\log }_{10}}2\] 
• D.            \[2.3\times 900\,R{{\log }_{10}}2\]