Solution:
Concept: Since it influences how far real gases deviate from ideal behaviour, compressibility factor is a crucial factor in real gases. Z stands for it. It is displayed in two ways: pressure variation at constant temperature and pressure variation at various temperatures.At high pressure, all gases show a positive deviation for ideal behaviour. So, the value of Z > 1.
At intermediate pressure, the value is Z < 1, due to negative deviation.
Only methane and carbon monoxide exhibit Z<1 for specific pressure ranges. For all pressure values, all other gases have a Z>1 value. A gas behaves more like an ideal gas as its temperature rises because the intermolecular forces of attraction weaken more and more when heat is added to the system.
Hence, the correct answer is option 4.