Saturated solution of benzene in water is in equilibrium with a mixture of air and vapours of benzene and water at room temperature and pressure. Mole fraction of benzene in liquid is x_B and the vapour pressures of benzene and water at these conditions are P_v^B and P_v^w respectively. The partial pressure of benzene in air-vapour mixture is

A. P_v^B

B. X_B.P_v^B

C. (P_atm - P_v^w)x_B

D. X_B.P_atm

Answer: Option B