The molecules of a given mass of a gas have rms velocity of `200 m//s at 27^(@)C and 1.0 xx 10^(5) N//m_(2)` pressure. When the temperature and pressure of the gas are respectively `127^(@)C and 0.05 xx 10^(5) Nm^(-2)`, the rms velocity of its molecules in `ms^(-1)` is
A. `200 ms^(-1)`
B. `400 ms^(-1)`
C. `200sqrt2ms^(-1)`
D. `400sqrt2ms^(-1)`
