Correct Answer - C::D
`DeltaU = 0` (Adiabatic)
`U = const`
`nC_(v)T = const`
As `O_(2)` and `N_(2)` are diatomic, so there temp are equal but is different from He
For a adiabatic `PV^(gamma) =const`
For `O_(2),N_(2)` value of `gamma` is same `:.` pressure of `O_(2),N_(2)` remains same but different form He