2. Ethanol is extracted from an ethanol-benzene solution containing 40% ethanol using water in a parallel flow multistage extraction unit. The raffinate (R1) taken from the first stage is contacted with the fresh solvent (water) in the second stage. Since the mass ratio of R1/water is 75/20, what is the raffinate concentration at the exit of the 2nd stage (R2)? a) 1% benzene, 12% ethanol, 87% water b) 1% benzene, 24% ethanol, 75% water c) 84% benzene, 13% ethanol, 3% water d) 95% benzene, 4% ethanol, 1% water Leave blank