The value of CP – CV is 1.00 R for a gas sample in state A and is 1.08R in state B. Let PA, PB denote the pressures and TA, and TB denote the temperatures of the states A and B respectively. Most likely
For gas in state A, Cp - Cv = R. This represents an ideal gas. Now, for an ideal gas, we require very high temperature and very low pressure compared to a real gas
For gas in state B, Cp - Cv = 1.08R, which represents a real gas. Since gas A was ideal, its pressure must be much lower than that of B and temperature must be much higher than that of A.
Hence, we require the condition pA < pB and TA > TB. This is given by option (a).
Options (b), (c) and (d) are incorrect because none of those satisfies the conditions for an ideal gas.