ANS:C - is independent of pressure.

In the case of non-ideal gases and liquids, the molal diffusivity does not have a simple relationship with pressure. However, it can vary depending on the specific conditions and properties of the system. Therefore, none of the provided options accurately describe the behavior of molal diffusivity in non-ideal systems. Molal diffusivity is a measure of the rate at which a solute diffuses through a solvent and is typically expressed in units of m²/s. It depends on various factors such as temperature, pressure, concentration, and the interaction between solute and solvent molecules. Therefore, the statement "is independent of pressure" is the closest approximation among the provided options, but it is not entirely accurate since molal diffusivity can be influenced by pressure in some cases, especially at high pressures or under specific conditions.