Gases such as air, nitrogen and oxygen can be roughly defined as perfect gases because they:

Gases like air, nitrogen, and oxygen are often referred to as perfect gases because they closely follow the ideal gas laws under many conditions. The correct choice indicates that these gases remain in a gaseous state because they are sufficiently removed from their condensation temperature. This aspect highlights their behavior under typical atmospheric conditions, where they do not condense into liquids.

When a gas is well above its condensation temperature, it behaves more like an ideal gas, meaning its molecules are adequately spaced apart and interact minimally with one another. This allows for simplifications in calculations involving pressure, volume, and temperature, making these gases accurately described by the ideal gas equation (PV=nRT).

The other options relate to gas behavior but do not accurately encapsulate the key characteristic of perfect gases as per the ideal gas assumptions. For instance, the ability to condense rapidly or expand without heating does not directly reflect the characteristics that define a gas as perfect, nor does the concept of superheating accurately apply to the classification of these gases. Hence, the rationale behind option C being correct is rooted in the fundamental properties of gases that maintain their gaseous state away from condensation.