A gas `(lambda=1.3)` is enclosed in an insulated vessel fitted with insulating piston at a pressure of `10^(5)N//m^(2)` . On suddenly pressing the piston the volume is reduced to half the initial volume. The final pressure of the gas is
A. `2^(0.7)xx10^(5)`
B. `2^(1.3)xx10^(5)`
C. `2^(1.4)xx10^(5)`
D. None of these