A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is Φi yi P = Yi xi fi° where, Φ is a vapor fugacity component, Yi is the liquid activity co-efficient and fi° is the fugacity of the pure component i. the Ki value (Yi = Ki xi) is therefore, in general a function of

• A. emperature only
• B. emperature and pressure only
• C. emperature, pressure and liquid composition xi only
• D. emperature, pressure, liquid composition xi and vapour composition yi