ANS:D - none of these

When the statement mentions "none of these" in the context of liquid-liquid binary diffusion, it means that the diffusivity of one constituent into another is not dependent on any of the factors listed previously: temperature and pressure, concentration, or nature of the constituents. In other words, none of these factors have a significant influence on the diffusivity of one liquid constituent into another in liquid-liquid binary diffusion. This statement implies that the diffusivity is primarily governed by other factors not mentioned in the list. In liquid-liquid binary diffusion, the diffusivity of a solute into a solvent is largely determined by properties such as the molecular size, shape, and polarity of the solute and solvent molecules, as well as the viscosity and density of the liquids. These factors influence the ease with which molecules can move through the liquid medium and interact with each other. Therefore, by stating "none of these," it emphasizes that while factors like temperature, pressure, concentration, and the nature of the constituents can affect diffusion processes in other contexts, they do not significantly impact the diffusivity of one liquid constituent into another in liquid-liquid binary diffusion. Instead, other properties and characteristics of the liquids and their interactions govern the diffusion behavior in this specific scenario.